Compositesworld - Gardner Business Media

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Table of Contents
October 2013
| Vol. 18 | No. 5
COMPOSITES
WATCH
Marine | 9
Wind Energy | 10
Construction | 12
22
News | 15
COLUMNS
Editor | 3
CT goes to SPE ACCE
Composites: Perspectives
& Provocations | 5
By the Numbers | 7
30
46
DEPARTMENTS
22
FEATURES
Work In Progress | 16
Structural Preform Technologies
Emerge from the Shadows
Applications | 41
Not yet in full production, with one exception, all are aimed at accelerating composite part
manufacture at fast automotive rates.
By Sara Black
New Products | 43
Calendar | 42
Marketplace | 44
Showcase | 45
30
Wind Blades | Progress & Challenges
36
Inside Manufacturing
Maximum Thrills | Minimum Tools
Despite doube-digit wind energy industry growth, turbine blade manufacturers and materials
suppliers acknowledge a pressing need to reduce costs and innovate.
By Michael LeGault
Ad Index | 45
COVER PHOTO
46
Engineering Insights
Composite Submarine Camels
Win with Long-term Durability
The U.S. Navy wisely opts for more expensive submarine moorings that maximize lifecycle
cost-efficiency.
By Jeff Sloan
The 360Rush water slide at Spring Valley
Beach amusement park in Blountsville,
Ala., was designed by SplashTacular (La
Quinta, Calif.). Cape Coral, Fla.-based
composite tooling supplier JRL Ventures
demonstrated that tooling costs can be
greatly reduced by producing parts of
multiple sizes from a resizable mold and
a single, reusable vacuum bag (see p. 36).
Source | SplashTacular
CT OCTOBER 2013
Water slide manufacturer’s disastrous fire loss opens door to a closed molding process that
reduces the number — and cost — of production molds, promising future gain.
By Michael LeGault
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Editor
EDITORIAL OFFICES
Richard G. Kline, Jr. / [email protected]
Jeff Sloan / [email protected]
Mike Musselman / [email protected]
Sara Black / [email protected]
Lilli Sherman / [email protected]
Ginger Gardiner / [email protected]
Susan Kraus / [email protected]
Kimberly A. Hoodin / [email protected]
Midwestern U.S. & International Sales Office
Associate Publisher Ryan Delahanty / [email protected]
Eastern U.S. Sales Office
District Manager
Barbara Businger / [email protected]
Mountain, Southwest & Western U.S. Sales Office
District Manager
Rick Brandt / [email protected]
European Sales Office
European Manager Eddie Kania / [email protected]
Contributing Writers
Dale Brosius / [email protected]
Donna Dawson / [email protected]
Michael LeGault / [email protected]
Peggy Malnati / [email protected]
Karen Wood / [email protected]
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compositesworld.com
Richard G. Kline, CBC | President
Melissa Kline Skavlem | COO
Richard G. Kline, Jr. | Group Publisher
Tom Beard | Senior V.P., Content
Steve Kline, Jr. | Director of Market Intelligence
Ernest C. Brubaker | Treasurer
William Caldwell | Advertising Manager
Ross Jacobs | Circulation Director
Jason Fisher | Director of Information Services
Kate Hand | Senior Managing Editor
Jeff Norgord | Creative Director
Rhonda Weaver | Creative Department Manager
Dave Necessary | Senior Marketing Manager
Allison Kline Miller | Director of Events
ALSO PUBLISHER OF
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• NPE Official Show Directory
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• Automotive Design & Production
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CT goes to
SPE ACCE
This year, the Society of Plastics Engineer’s Automotive Composite Conference &
Exhibition (ACCE) was relocated from the outgrown Michigan State University
Management Education Center (Troy, Mich.) to the Suburban Collection Showcase in nearby Novi. A good thing. ACCE exhibitors doubled, and last year’s record
630 attendees paled compared to the 897 registered this year — one indication
that auto OEMs could be ready for pervasive use of composites. CT staffers went
looking for answers to the question I asked in my August editorial: Are we ready?
The best answer may be, We know what we need to do to be ready.
Managing editor Mike Musselman says many at ACCE considered that very
question. ACCE co-chair Ed Bernardin (Siemens PLM Software) said the auto
industry’s characteristic high rate of change is a key hurdle. He and Roger Assaker
(e-Xstream engineering) contended that virtual testing of composites is a huge need
in the auto world. Such tools are well developed for chopped-fiber compounds, but
there is a pressing need for software that can simulate failure of continuous-fiber
composites. Reliable tools are emerging and will, says Assaker, take a two-year,
multimillion dollar testing program and
compress it into a long work day!
We know what we need
High-pressure RTM (HP-RTM), the
to do to be ready.
subject of multiple research reports at last
year’s ACCE, is now commercial: Shuler
SMG GmbH’s vacuum-assisted HP-RTM system mints the BMW i3 passenger cell
and the BMW M3 roof. Quickstep Technologies proposes to do similar duty at low
pressures (and with less expensive equipment), with the aid of fluid heating and its
new Resin Spray Technology (RST). And Volkswagen AG’s Hendrik Mainka said
his work with Oak Ridge National Lab shows that lignin precursor and the process
of oxidation and pyrolization that converts it to carbon fiber spells cost savings of
40 percent. Unfortunately, unresolved issues, among them the seasonal variation in
lignin (as a plant product), mean commercialization could be a decade away.
CT senior technical editor Sara Black points out that ACCE’s “Aluminum &
Composite — Compete or Collaborate?” panelists included aluminum industry
representatives. All the panelists agreed that composites can 1) displace steel and
aluminum in appropriate applications, and 2) make invaluable contributions to
lightweighting. But the discussion revealed that auto OEMs will remain resistant
until they hear a valid value proposition. If a composites solution for automotive
can make a part lighter, for less money, no problem, say the OEMs. Such solutions,
so far, are scarce — a notable exception is the semi-convertible sunroof frame for
the Citroen DS3 Cabrio, molded from a modified glass-reinforced styrene maleic
anhydride (SMA) resin. The part offers significant material cost savings, part integration (seven parts combined into one) and a 40 percent weight reduction. That
aside, Kaiser Aluminum’s Doug Richman made the point that without a solid business case, it’s impossible to make the technology case. Panelist Jai Venkatesan of
Dow Chemical Co., pointed out in his keynote address that adoption of composites is a “high-risk, high-reward” and disruptive step, and it’ll take time. Yet, he
believes that we can use lessons learned
from veterans of aerospace composites and
automotive aluminum, apply software tools
more widely, and — in collaboration —
Jeff Sloan
eventually ensure that composites become
an entrenched material choice.
CT OCTOBER 2013
Publisher
Editor-in-Chief
Managing Editor
Technical Editor
Senior Editor
Senior Editor
Graphic Designer
Marketing Manager
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Composites: Perspectives & Provocations
The positive consequences
of regulating styrene
Bio | Dale Brosius
Dale Brosius is the head of his own consulting company and
the president of Dayton, Ohio-based Quickstep Composites,
the U.S. subsidiary of Australia-based Quickstep Technologies (Bankstown Airport, New South Wales), which develops
out-of-autoclave curing processes for advanced composites.
His career includes a number of positions at Dow Chemical, Fiberite and Cytec, and for three years he served as the
general chair of SPE’s annual Automotive Composites Conference and Exhibition (ACCE). Brosius has a BS in chemical engineering from Texas
A&M University and an MBA. Since 2000, he has been a contributing writer for
Composites Technology and sister magazine High-Performance Composites.
Technology (MACT) standards, was met initially by strong opposition from the composites industry supply chain, citing large reductions in industry employment and loss of competitiveness against
foreign rivals that aren’t restricted by such legislation.
Having observed the long-term effects of these regulations, I
am firmly of the opinion that their consequences have been mostly
positive, well beyond worker safety and reduction of VOCs. How?
The quality and performance of composites produced with polyesters and vinyl esters have greatly improved, making composites
ever more competitive against traditional materials, such as wood,
concrete and metals. I’m not sure these advances would have been
achieved if the industry hadn’t been pushed out of its comfort zone.
Take, for example, the large-scale migration from open moldn 1859, Thomas Austin imported 24 wild rabbits from England
ing to closed molding, in particular, the growth of vacuum resin
and released them into the Victoria, Australia, countryside to
infusion (in all its various forms and acronyms). Rather than thick,
provide animals for sport hunting. The rabbits, doing what rabbits
resin-rich parts made by chopper guns and manual rolling, today’s
notably do, multiplied voraciously, destroying vegetation and crops
boats, bridge decks, wind turbine blades and pollution-control sysas they spread north and west across the continent. With no natural
tems incorporate structural multidirectional fabrics and use less
predators in Australia, the rabbit population rose to an estimated 10
resin, yielding thinner, lighter and stronbillion by the late 1920s. The world’s
The performance of composites
ger structures. A whole industry has delongest rabbit fence, stretching 1,138
veloped to support large-part infusion,
miles/1,831 km from north to south
produced with polyesters and
resulting in greater competitiveness and
in Western Australia, was erected
vinyl esters has greatly
new jobs. Where open molding is still
with only limited success. Although
improved, making composites
preferred, sprayup is done by robots
Austin’s intentions might have been
following a preprogrammed path. The
good, the outcome was anything but.
ever more competitive.
result is less part-to-part variation and
Such stories exemplify the proverless resin use. Styrene contents of 45 percent used to be standard.
bial law of unintended consequences, in which what is believed to
Reformulation and new chemistries have reduced this to 25 to 30
be a simple solution to a problem runs into a complex system of inpercent in many cases. Filament winding, pultrusion and compresteractions that leads to a negative outcome. A more recent example
sion molding also have benefitted from these new resins. Workers
is regulation that drives the production of ethanol as a fuel additive
are better protected, fewer VOCs are emitted, and the industry is
to reduce oil imports, but then drives up the demand for corn, remore competitive.
sulting in higher food prices.
We have all of the above thanks to an industry full of talented
Some argue that government regulations always have detrimenscientists and engineers, and the future of styrene-diluted compostal consequences, but one only has to visit Shanghai, China, to be
ite resins looks positive. But there is still one major battle to fight:
reminded that the 1970 Clean Air Act in the U.S. has been a positive
the listing of styrene as a suspect carcinogen in the 12th Report on
for our major cities. There was considerable gnashing of teeth and
Carcinogens (ROC), issued by the National Toxicology Program
claims of economic peril in the wake of the law’s passage, but out
(NTP). Fortunately, through the excellent efforts of the American
of the law arose a lot of new pollution-control technology, both for
Composites Manufacturers Assn. (ACMA, Arlington, Va.) and othautomobiles and smokestack industries. The composites industry
er industry groups, the National Research Council (Washington,
benefitted because of the inherent corrosion resistance of polyesters
D.C.) has agreed to conduct a peer review of the NTP’s listing. Here
and vinyl esters used in scrubbers and effluent piping.
is a situation where we should not err on the side of caution. Instead,
In the composites industry, we have seen several decades of regwe should trust the real science that shows styrene is safe, and I am
ulations targeting styrene, out of concern about air pollution and
optimistic that the right outcome will prevail.
suspected carcinogenic toxicity. Styrene is an extremely important
And that rabbit problem in Australia? Through the introduction
and cost-effective reactive diluent for polyester and vinyl ester resof virus-carrying insects starting in the 1950s, today’s population is
ins, enabling the low viscosities needed to promote flow, sprayabilestimated at 200 million, a 98 percent reduction since 1930. It’s one
ity and wetout of fiberglass and other reinforcements. Legislation,
more example of good science and innovative technology meeting
starting with California’s Proposition 65 and the later U.S. Environthe challenge. | CT |
mental Protection Agency’s (EPA) Maximum Achievable Control
CT OCTOBER 2013
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By the Numbers
Composites Business Index 48.2:
Contraction begins to slow
Bio | Steve Kline
Steve Kline is the director of market intelligence for Gardner Business Media Inc. (Cincinnati, Ohio), the parent company and publisher of Composites Technology magazine.
He started as a writing editor for another of the company’s
magazines before moving into his current role. Kline holds
a BS in civil engineering from Vanderbilt University and an
MBA from the University of Cincinnati.
employees had, through July, contracted four straight months. The
smallest facilities (fewer than 19 employees) contracted in July at the
fastest rate since the CBI began in December 2011.
In July, the strongest region for the year was the West North Central, which had grown for five straight months. The Mountain region
experienced the fastest growth rate in July, and it was its first month of
growth since February this year. All other regions contracted in July.
Future capital spending plans were at their second lowest level in
July since June 2012. Planned spending was more than 25 percent
above the historical average. Compared to July 2012, spending plans
n July, the Composites Business Index (CBI) of 47.7 indicated
in July 2013 were up by 16.1 percent.
that composites business activity in the composites industry
In August, a CBI of 48.2 showed that composites industry busihad contracted for the second consecutive month, having moved
ness
activity had contracted for the third consecutive month, but
steadily lower since it had peaked in March. Employment was the
the
rate
of contraction had slowed, indicating a possible break with
only index to make a positive contribution in July, expanding for
its
downward
trend. Two subindices made positive contributions:
the fifth straight month. All other subindices performed worse in
Employment
grew
for the sixth straight month, and suppler deliverJuly than in June. New orders contracted for the third month and
ies
continued
their
long-term lengthening trend. Production and
at a slightly faster rate. Production moved from growth to contracexports
continued
to
contract in August but did so at slower rates.
tion for the first time this year. Backlogs continued to contract,
Exports,
in
particular,
had contracted at a steadily slower rate since
and did so more significantly and at their fastest rate for the year
December 2012. New orders conTHE COMPOSITES BUSINESS INDEX
tracted for the fourth consecutive
month. The only subindex to negaSubindices
August
July
Change
Direction
Rate
Trend
tively impact the CBI was backlogs.
New Orders
47.4
47.4
0.0
Contracting
Flat
4
In August, it contracted for the 15th
Production
49.0
48.0
1.0
Contracting
Slower
2
month and had done so noticeably
Backlog
39.7
41.0
-1.3
Contracting
Faster
15
faster each month since February.
Employment
51.9
51.1
0.8
Growing
Faster
6
Material prices increased in
Exports
48.3
46.7
1.6
Contracting
Slower
16
August at their slowest rate since
Supplier Deliveries
52.6
51.7
0.9
Lengthening
More
21
November 2012. Prices received
increased slightly after decreasing
Material Prices
58.4
64.5
-6.1
Increasing
Less
21
three of the previous four months.
Prices Received
50.3
48.3
2.0
Increasing
From Decreasing
1
Future business expectations fell
Future Business
65.4
67.8
-2.4
Improving
Less
21
somewhat after having stayed fairly
Expectations
level for six months.
Composites
48.2
47.7
0.5
Contracting
Slower
3
One month does not a trend
Business Index
make, but activity based on plant
size could be shifting. Fabricators with more than 250 employees
to date. Exports remained mired in contraction. Supplier deliveries
contracted for the first time since November 2012. Those with fewer
lengthen in July, having done so at a fairly constant rate all year.
than 19 employees continued to contract, but at a much slower rate.
Material prices increased in July. The rate of increase reached
The small facility index, however, moved up to 43.9 from 38.9 in
its fastest pace since March. Prices received by composites fabricaJuly. Those with 50-249 employees continued strong.
tors decreased for the third time in four months. The combination
Four regions expanded in August. The fastest rate was the West
of increasing material prices and decreasing prices received had a
South Central, which had grown five of the previous seven months
significant negative impact on profitability. But future business exand, thus, was 2013’s best performer to date. Meanwhile, New Engpectations improved noticeably in July. They reached their second
land, the South Atlantic and the Middle Atlantic all moved from
highest level since May 2012.
contraction to expansion. But the West North Central, which had
The business activity this year through July was much higher at
strong growth the previous five months, fell off sharply.
large than at small facilities. Those with more than 250 employees
Future capital spending plans were just above the historical avhad grown at a consistently strong rate since December 2012. Facilierage in August. However, the month-over-month rate of change
ties with 50 to 249 employees had grown in all but a couple of months
contracted for the third time in five months. | CT |
in that same time period. However, fabricators with fewer than 50
CT OCTOBER 2013
I
7
COMPOSITES WATCH
Composites
WATCH
Whether it’s the marine market, the wind energy industry, urban
MARINE
infrastructure or the composites supply chain, the key word is change.
MARINE market’s glass half full, half empty
Source | Delta
No end-market served by the
composites industry was harder
hit by the recession than marine.
Since 2008, demand for boats of all types has dropped
dramatically. U.S.-based BoatingIndustry.com hosted a
webinar in August in which three speakers agreed that
the marine segment could take a while to return to the
peaks seen in 2005-2006. Jim Petru, director of industry
statistics and research at the National Marine Manufacturers Assn. (NMMA, Chicago, Ill.); Peter Houseworth, director of client services at Info-Link (Miami,
Fla.); and Jon Burnham, editorial director at Dominion
Marine Media (Norfolk, Va.) noted a number of positives: Boating participation has been up 32 percent in
the past five years, 81 percent of boat owners have
annual incomes of less than $100,000, powerboat sales were up
10 percent and sailboat sales were up 29 percent in 2012. Further,
the total U.S. recreational marine craft sales were $35.6 billion
in 2012, up from $32.4 billion in 2011, but still shy of the 2006
peak of $39.5 billion.
That said, they spied troubling trends as well: Each year,
the average age of boat owners increases by six months. Tradtional powerboat sales are in decline, with 157,000 units sold
in 2012, compared to more than 500,000 units sold in 1988.
The average powerboat age today is 21 years, compared to 15
years in 1997, and 74 percent of sailboats are more than 20 years
old. The total number of marine vessels registered in the U.S. hasn’t
changed in 15 years, despite a 25 percent population increase, and
7 out of 10 first-time boat buyers sell their boat and leave the sport.
Lastly, aging baby boomers, a long-time major consumer of boats,
are less active in the sport.
Analysts suggest that the aging fleet might signal that consumers
are on the verge of upgrading to new boats, propelling the market
into high-growth. Petru noted during the webinar that overall boat
sales correlate to consumer confidence. Because that confidence is
coming back slowly and the market is awash with quality used boats
for sale, the marine industry’s growth will likely continue to be slow.
The Society for the Advancement of Material and Process Engineering (SAMPE, Covina, Calif.) and the American Composites Manufacturers Assn. (ACMA, Arlington, Va.) announced on July 31 that
their new jointly owned and operated trade show and conference
will be called CAMX — the Composites and Advanced Materials
Expo. SAMPE and ACMA, which traditionally have operated their
own trade shows, announced late in 2012 that they would consolidate the former SAMPE show and ACMA’s COMPOSITES show
into a single fall event, beginning in 2014.
SAMPE brings with it composites professionals who primarily
serve the aerospace market and other advanced materials applications. ACMA has served a broad range of applications, including
those in the marine, wind energy, automotive, infrastructure and
industrial markets. Going forward, CAMX is expected to be North
America’s composites industry go-to event for every served market segment. The newly partnered organizations say the trusted and
valued aspects of both organizations’ annual events will continue at
CAMX in an expert-rich combined technical conference program,
and a far more expansive show floor. The first CAMX conference
program will take place Oct. 13-16, 2014, and the CAMX exhibit
hall will be open Oct. 14-16, at the Orange County Convention
Center in Orlando, Fla. CAMX 2014 is expected to attract more
than 8,500 attendees and more than 500 exhibitors. For more information, visit the CAMX Web site at www.thecamx.org.
CT OCTOBER 2013
SAMPE/ACMA joint trade show christened CAMX
9
ENERGY
COMPOSITES WATCH
WIND BLADE joint venture to
supply Europe and North Africa
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COMPOSITESWORLD.COM
Source | Nordex
TPI Composites (Scottsdale, Ariz.) announced
on Aug. 13 that it had signed a multiyear supply agreement with
Nordex SE (Hamburg, Germany) under which it will provide
blades for Nordex’s N117 wind turbine from TPI’s factory in
Izmir, Turkey. Nordex will use the blades for projects in Turkey
and export them to other locations in the greater European region,
northern Africa and the Middle East.
TPI and ALKE ÎNŞAAT, an engineering, manufacturing and
construction company headquartered in Istanbul, Turkey, formed
a joint venture company in Izmir to manufacture large blades in
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Tel: +1 408 776 0700
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Tel: +1 805 482 1722
www.tencateperformancecomposites.com
www.tencateadvancedcomposites.com
E-mail: [email protected]
COMPOSITES WATCH
CT OCTOBER 2013
2012. The joint venture, TPI Kompozit Kanat Sanayi ve Ticaret
A.S., has a 355,000-ft2 (32,500m2) building with convenient access
to both land and water transportation, which enables cost-effective
export of blades to southern and eastern Europe and northern Africa. TPI Composites controls and operates the Turkish joint venture.
“We are thrilled to add Nordex as a key customer of our Turkey operation under TPI’s partnership model,” says Steve Lockard,
president and CEO of TPI Composites. “Nordex is a leader in the
Turkey and European wind markets. Their N117 turbine is one of
the most advanced and efficient in its class with average capacity
factors in excess of 35 percent.” Dr. Juergen Zeschky, CEO of Nordex, adds, “We are very pleased to be partnering with TPI in Turkey
to provide world-class wind blades to the region. TPI’s track record
as a technology and quality leader makes them an excellent partner
to match the performance and reliability of Nordex wind turbines.”
Related to wind energy market growth in Eurasia, Reuters
reported on Aug. 26 that wind turbine and blade producer Siemens (Munich, Germany) expects the global wind power market
to more than quadruple by 2030, lifted by strong growth in Asia.
Markus Tacke, chief executive of Siemens’ wind power division,
said at a renewable energy conference in Berlin that “the market
will shift away from Europe significantly,” according to the story
by Christoph Steitz. Tacke added that globally installed wind power capacity would increase to 1,107 GW in 2030 from 273 GW in
2012, with the Asia-Pacific region accounting for more than 47
percent of the total, up from 34 percent now.
11
CONSTRUCTION
COMPOSITES WATCH
New composite reinforcing
grid enables thinner concrete
façade panels
FREKOTE® LEAVES OTHER
MOLD RELEASE PRODUCTS
IN ITS WAKE
Composite manufacturers depend on Frekote® mold release
agents because they:
Ɔ allow multiple releases per application
Ɔ result in a clean, hi-gloss finish
Ɔ are fast curing
Ɔ reduce downtime/ increase productivity
Ɔ decrease rejection rates/ improve quality
Ɔ lower manufacturing costs/boost profitability
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710-LV™ a solvent-based mold release agent with low VOCs,
high slip with non-contaminating transfer, no mold buildup.
FMS-100™ a streak-free, solvent-based mold release sealer
that offers ease of application, high gloss finish and fast cure.
Eliminates porosity/micro porosity, and even seals “green”
molds and repaired areas.
COMPOSITESWORLD.COM
AQUALINE®&˝ȆȀȀ™ a water-based emulsion that sets the
standard for water-based release agents. Nonflammable.
Multiple releases per application.
12
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Source | SGL
A 3-D carbon fiber reinforcement recently developed by SGL
Group - The Carbon Co. (Wiesbaden, Germany) and V. FRAAS
Solutions in Textile GmbH (Helmbrechts, Germany) has recently
proven its worth. SGL reported on Aug. 16 that it is possible to
produce concrete façade panels only 26 mm/1.02 inches thick
using a “carbon grid” as internal reinforcement. The grid consists
of two plies of carbon fiber scrim spaced 12 mm/0.47 inch apart
that are connected by compression-resistant pile threads. A steelreinforced facade panel of similar size reportedly has a minimum
thickness of 100 mm/3.94 inches — the extra thickness is necessary to prevent corrosion of the steel due to water ingress by way
of cracks in the concrete.
The thin facade panels were installed on a new factory for Alphabeton AG in Büron, Switzerland, an innovative specialist in
concrete products manufactured from high-performance and
ultrahigh-performance concrete (UHPC). A ventilated façade
“curtain wall” was installed on the building, with a total area of
450m2/4,844 ft². The wall comprises 350 panels, each measuring 865 by 1,620 mm (34 by 63.8 inches), with a thickness of 26
mm/1.02 inches. The building, appropriately, houses a precast
concrete element production line.
“We were looking for a solution that would enable us to produce thin concrete façade panels in large dimensions,” says Alphabeton’s Hans-Peter Felder, who is responsible for R&D. “The new
3-D carbon fiber grids impressed us with their light weight and
corrosion resistance and were easy and convenient to process.”
Peter Weber, VP of sales and marketing for SGL’s Carbon Fibers & Composite Materials business unit, adds, “In this application, we particularly exploit the corrosion resistance of our carbon fibers. Thanks to this advantageous property, we can dispense
with the thick concrete covering obligatory with steel-reinforced
concrete to prevent rust and produce thin concrete elements.”
V. FRAAS has developed a production plant in which the new
3-D textile reinforcement is manufactured with SGL’s SIGRAFIL
C carbon fibers, in large dimensions. The structural grids are also
being used in the repair and renovation sector and in bridges and
buildings, says V. FRAAS.
COMPOSITES WATCH
PEOPLE BRIEFS
Competence in composites:
We have better solutions
for making cars lighter
I T ES
P OS E
M
CO ROP 13
E U 9. 2 0
art,
19.0
17.– Stuttg
e
s
y
s
Me erman
G
With our new, innovative D-SMC and
HP-RTM processes, we are continuously
advancing global progress in series production of lightweight components with
glass or carbon fibre-reinforced plastics.
www.dieffenbacher.com
CT OCTOBER 2013
Stephen Browning, PE, joined Strongwell Corp. (Bristol, Va.) as a structural engineer. He has a BS in civil engineering technology from Bluefield
State College, a BS in civil and environmental engineering from Tennessee Tech University and an MS in civil engineering from Virginia Tech.
From 2004 to 2013 he operated his own construction design/consulting
business … The Composites Group (Highlands Heights, Ohio) realigned
its senior management. Hector Diaz-Stringel was promoted to VP of
manufacturing operations. He worked in the chemicals industry before
joining the company as corporate director of manufacturing operations
in 2012. Diaz-Stringel holds a BS in chemical engineering and management from the Monterrey Institute of Technology and Higher Education
(Monterrey, Mexico) and an MBA from Kent State University. Dwight
Morgan became VP of sales and marketing. He began his career with
M.A. Hanna Co. (Cleveland, Ohio), now Avon Lake, Ohio-based PolyOne
Corp., then formed color and additive formulator Accel Color Corp. (Naperville, Ill.), now part of Techmer PM LLC (Clinton, Tenn.). Morgan holds
a BA from Kent State University’s School of Journalism and a JD from the
University of Akron School of Law. Company veteran Marc Imbrogno
was promoted to corporate director, market/product development. He
began his career as an R&D chemist at Cleveland, Ohio-based Glastic
Corp. and then joined BASF (Florham Park, N.J.). He holds a BS in chemistry from the University of Akron … Robert Scarpitto has joined the
Interplastic Corp. (St. Paul, Minn.) sales team as a sales representative
responsible for California, Nevada and Baja California, Mexico. He brings
to the position more than 20 years in a variety of sales positions.
13
COMPOSITES WATCH
Composites
NEWS
Chem-Trend acquires Zyvax, Dieffenbacher buys Fiberforge, Axson US integrates CASS Polymers
Chem-Trend (Howell, Mich.), reported on July 15 that it has acquired more specifically, in North America. Axson will continue to offer
Zyvax Inc. (Ellijay, Ga.). Zyvax will become a brand within the Chem- the TCC, ADTECH Plastic Systems, ADTECH Marine and SparTrend product mix.
tite lines, which include well-known trademarked products, such as
Zyvax was founded in 1985 by Nancy Layman, who was an early Model Plank, Pattern Plank, Die Plank, Fixture Plank, ProBuild and
leader in, and dedicated most of her career to, developing specialty other ADTECH Marine products.
release systems for the composites
industry. Zyvax was first to market with
a line of solvent-free, water-based release
systems engineered to meet the require• Over 40 types of
ments of advanced composite processes.
fixtures in stock,
Layman is working with Chem-Trend and
ready to be shipped.
Zyvax customers for a successful integra• Expert consultation
tion of the Zyvax product line into the
with Dr. Adams
• Email or call today
Chem-Trend portfolio.
to discuss your fixture
Dieffenbacher (Eppingen, Germany)
and custom design needs.
INC.
reported Sept. 13 that it had purchased
machinery, expertise and intellectual property rights to the Relay automated tapeStandard fixtures are kept
laying technology, developed by recently
in stock like our:
shuttered Fiberforge (Glenwood Springs,
Colo.) to lay up flat thermoplastic composLONG BEAM
ite “tailored blanks” for subsequent therFLEXURE
moforming as 3-D components.
TEST FIXTURE
Dieffenbacher intends to pursue applishown
with our optional
cations using fiber tape structures alone,
Alignment
Rods and Bearings
but also plans to integrate the tape layup
technology into its LFT-D system to create
ASTM C393/D7249
Tailored LFT-D technology. The resulting
components, with local UD-fiber tape reCelebrating
inforcement for specific applications, will
25 Years
of Excellence
subsequently be integrated into large-scale
1988-2013
production lines to achieve high levels of
Custom designs are
structural rigidity at a low cost.
made to your
On Aug. 27, Axson Technologies (Cerspecifications
like our:
gy, France, and Eaton Rapids, Mich.) announced that it has acquired CASS PolyREVERSED
mers of Michigan Inc. (Madison Heights,
LOADING
Mich.). It will be integrated into Axson
US Inc. (Eaton Rapids, Mich.), and Axson
FLEXURAL
Technologies will manage the acquired
FATIGUE
business and brands, which include Tool
TEST FIXTURE
Chemical Composites (TCC), ADTECH
Plastic Systems, ADTECH Marine Systems
Dr. Donald F. Adams
2960 E. Millcreek Canyon Road
and Spartite.
President
Salt Lake City, UT 84109
According to Axson, the acquisition
45
years
of
Phone (801) 484.5055
fortifies its focus on providing high-perComposite Testing Experience
Fax (801) 484.6008
formance polymer formulations to the
email: [email protected]
tooling, prototyping, structural adhesive
www.wyomingtestfixtures.com
and composites markets globally and,
CT OCTOBER 2013
W yoming
T est
F ixtures
15
Work
Work in
in Progress
Progress
Wind
blades
Pi preforms
increase shear
web failure load
Easily co-infused structural joint increases ultimate strength and fatigue life,
offering solutions for designers as blades get longer and move offshore.
W
ind blades are commonly made by infusing top and
bottom blade shells separately, then adhesively bonding
them together around a prefabricated shear web.
The current state of the art leaves much to be desired. The typical
construction is essentially an I-beam, in which a C-shaped shear
web provides an area for adhesive bonding to spar caps that are
co-infused with the blade shell. Typically, the C-beam must be
braced with additional L-beams during assembly (see left image, top
of p. 25). After epoxy paste adhesive is applied to the bottom blade
half and the shear web, their surfaces are mated, and sufficient time
must be allowed for cure. Then, adhesive is applied to the top blade
half, the upper surface of the shear web and the leading and trailing
edges. Again, the adhesive surfaces are mated, and time is required
for cure. This multistep process requires significant labor and time.
Additionally, when the top half of the blade is lowered onto the
bottom half, the joints are mated blindly, that is, without visual
or other access to the bonding areas. Industry presentations and
patents list other shortcomings and clearly state that blade designs
would benefit from an improved bond configuration between the
shear web and spar cap.
Textile manufacturer 3TEX (Cary, N.C.) began work on such a
configuration several years ago as part of a Small Business Innovation Research (SBIR) project awarded by the U.S. Department of
Energy (DoE, Washington, D.C.), using the Pi joint concept that
was demonstrated in the Air Force Research Lab’s (AFRL, Dayton,
Ohio) Composites Affordability Initiative (see “Learn More,” p. 29).
Composite
shell
Spar
Supporting spar
Adhesive layer
Composite shell
16
Wind blade structural elements are typically a shaped shear web
bonded to spar caps co-infused into top and bottom blade shell
halves. The thick and uneven adhesive layers limit the strength of
the joint and create reliability and repair issues.
Source | Linxia Gu, University of Nebraska-Lincoln
COMPOSITESWORLD.COM
WHY PI?
3TEX cites two reasons for its use. First, the Pi joint (so named
because its primary component takes the shape of the Greek letter
π) have been shown in the aerospace industry to provide superior
strength in pull-test loads, compared to conventional laminated
joints. AFRL’s Dr. John Russell says the joint “provides symmetrical loads to the adhesive area and acts as a double lap-shear
joint, increasing the surface area for bonding.” Also, the primary
load in the adhesive bonds is located farther away from the area of
maximum strain. These factors combine, says Russell, to make the
Pi joint a more effective design. Pi joints also have demonstrated
high tolerance of several manufacturing defects associated with
Work in Progress
110 mm
7.6 mm thick
Pi preform
C-leg
L-shape
(7.2 mm thick)
Pi base
Pi leg
C-leg
300 mm
Adhesive Layer
(3.0 mm thick)
Balsa core
50 mm (12.4 mm thick)
Shear web skin
(3.8 mm thick)
Adhesive layer
(3.0 mm thick)
Flange
(8.1 mm thick)
Balsa core
(12.4 mm thick)
Shear web skin
(3.8 mm thick)
3TEX tested I-beams
made with a conventional
joint design (C-beam plus
L-shaped braces, at left)
vs. its new joint design
using a 3-D woven Pi
preform (right).
Adhesive Layer
(2.5 mm thick)
42.5 mm
Flange
(4.2 mm thick)
25 mm
200 mm
200 mm
blind mating, including excessively thick bondlines, voids, nonvertical alignment of the Pi legs or joint structure within the Pi, and
even peel plies that are not removed before bonding.
Second, a Pi joint, despite its complexity, can be preformed in
an automated process. 3TEX R&D director Dr. Keith Sharp says his
company’s 3D Weaving process “lends itself to easy manufacture of
Pi joint preforms. We simply design a textile with z-direction yarns
penetrating completely through the thickness for the center portion
and then only halfway through the thickness for the outer edges,
allowing these lengths to be folded up to form the two legs of the
Pi.” The dry preform is reportedly easy to co-infuse with the blade
shell so the legs of the Pi align vertically to receive and locate the
shear web. This permits the blade manufacturer to use a simple flat
plate for the web — C-shapes and L-braces are no longer necessary.
Therefore, blind mating of the joint surfaces is vastly simplified.
Co-infused Pi joint
and blade skin
Source | 3TEX
(8.1 mm thick)
by distributor LBI Inc. (Groton, Conn.). The Pi joints and web were
infused with Rhino 1401-21/4101-21 epoxy resin supplied by Rhino
Linings (San Diego, Calif.). When the Pi joints and web were bonded, the Pi joint slot was 2.5 mm/1 inch wider than the web to allow
sufficient space for the Rhino 405 Structural Epoxy Gel adhesive.
The conventional I-beam used in the test replicated the construction of a 13m/43-ft long commercial wind blade from Heartland Energy Solutions (Mount Ayr, Iowa). The C-shape shear web was made
with two faceskins of triaxial E-glass fabric (0˚/±45˚ with 0˚ oriented along the beam length), each measuring 3.8-mm/0.15-inch thick,
on each side of a 12.4-mm/0.5-inch thick balsa wood core. The material suppliers and infusion process were the same as those previously described. The top and bottom flanges of the C-beam were
formed by extending the two faceskins at 90o to the cored section.
The C-beam measured 7.6-mm/0.3-inch thick, and its height was
50 mm/1.97 inches. Two 7.2-mm/0.28-inch thick L-beams were
PI PROGRESS
CT OCTOBER 2013
Both types of 2.7m/8.9-ft beams were clamped and cantilever-loaded to
simulate wind blade service, during tests conducted at the Constructed
Facilities Laboratory at North Carolina State University.
Source | 3TEX
In a presentation at the 2012 SAMPE conference in Baltimore, Md.,
3TEX reported that preliminary performance testing was done by
fabricating composite I-beams made with the 3TEX 3-D woven
Pi preform joint and a conventional joint (C-beam plus L-shaped
braces, see top images, this page). The I-beams were 2.7m/8.9ft long by 0.3m/1-ft tall, with 0.2m/0.7-ft wide flanges, matching
the dimensions of the spar cap width and thickness and the shear
web height of a 13m/42.7-ft long commercial wind blade at the
10m/33-ft station. The flanges were 8.1-mm/0.3-inch thick E-glass/
epoxy laminate. A test apparatus was developed that clamped a standard I-beam at one end and applied an upward load at the other end
to simulate the dominant type of loading on a wind blade.
For the Pi joint I-beams, Pi preforms were woven as a single
E-glass fabric and split to form two 4.2-mm/0.2-inch thick legs,
each measuring 42.5 mm/1.7 inches in length and separated by an
8.1-mm/0.3-inch thick central section that was 25-mm/1-inch wide.
The 110-mm/4.3-inch wide preform had 54 percent total fiber volume fraction with equal amounts of fiber in both in-plane directions
and 1.5 percent in the z-direction. A 20-mm/0.8-inch wide flat plate
shear web was made, using 3.8-mm/0.2-inch thick faceskins of triaxial E-glass fabric from SAERTEX USA LLC (Huntersville, N.C.)
on each side of a 12.4-mm/0.5-inch thick balsa wood core, supplied
17
REGISTER TODAY!
Y!
DECEMBER 9-12, 2013
Join us in Knoxville, Tennessee for Carbon Fiber 2013!
Don’t miss this opportunity to learn from the industry’s leading
innovators and network with decision makers and key
executives from all aspects of the carbon fiber supply chain!
Plan to join us for a tour of Oak Ridge National Laboratory’s
carbon fiber manufacturing facility (optional).
CONFERENCE CO-CHAIRS:
ANDREW HEAD, President, A & P Technology Inc.
DOUG WARD, Consulting Engineer, Composites. GE Aviation
Sponsorships and exhibit space are available!
Contact Kim Hoodin, Marketing Manager, [email protected]
IN ASSOCIATION WITH:
SPONSORED BY:
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Knoxville, Tennessee, USA
LEARN!
CompositesWorld’s Carbon Fiber 2013 is the Carbon Fiber
conference organized by composites industry professionals!
Since 1998 the Carbon Fiber conference has successfully
been bringing together the industry’s leading executives and
technologists to explore the expanding role of carbon fiber
in the composites industry.
NETWORK!
Nowhere else will you have access to this timely and pertinent
information and to the industry’s top minds and innovators.
As you enjoy the catered networking functions at Carbon Fiber
2013 you will make invaluable contacts with the key executives
in the industry.
Pre-Conference Seminar*
CONFIRMED
PRESENTATIONS INCLUDE:
Producing Thermoplastic Matrix Composites
for Aeronautical Applications Under Industrial
Scale Conditions
ANGELOS MIARIS, Premium AEROTEC GmbH
Analysis and Optimization of Composite
Structures – Challenges and Opportunities
BRETT CHOUINARD, COO, Altair
Next Generation Carbon Fiber Composites:
Beyond Medium Volume
GARY R. LOWNSDALE, Chief Technology Officer,
Plasan Carbon Composites
Carbon Fiber Powering America’s Big Rigs
NEEL SIROSH, Chief Technology Officer,
Quantum Technologies Inc.
A Hybrid Composite/Metal Gear Concept
for Rotorcraft Drive Systems
GARY D. ROBERTS, Research Materials Engineer,
NASA Glenn Research Center
Alternative Precursors for Sustainable
and Cost-effective Automotive Carbon Fibers
HENDRIK MAINKA, Volkswagen Group of America, Inc.
Monday, December 9, 2013
Emerging Opportunities and Challenges for Carbon Fiber in Passenger
Automobiles – Is the CFRP Industry Ready for Mass Production?
Presented by:
Chris Red, Principal, Composites Forecasts and Consulting, LLC
The seminar provides a “grounds-up” analysis of the market and
opportunities for CFRP within the 75 million vehicles per year passenger
vehicle market over the next ten years (2013 – 2022), with a special focus on:
• Drivers and Limitations Influencing CFRP Usage
• Regional and OEM activity analysis
• CFRP applications (body, chassis, drivetrain, brakes, interiors, etc.) analysis
• Tier supplier activity
• Manufacturing process considerations
• CFRP component volumes and raw material requirements to support
forecasted automobile production.
*Separate fee required
REGISTER TODAY!
TO LEARN MORE OR REGISTER VISIT:
http://short.compositesworld.com/CF2013
Application and Processing of Complex Fabrics
for Lightweight Structures
CHRIS MCHUGH, Technical Manager, Sigmatex (UK) Ltd
Lighter, Stronger, Greener: How Carbon Fiber
is Modernizing Precast Concrete!
JOHN M.CARSON, Executive Director, AltusGroup, Inc
Carbon Fiber Usage in the Wind Energy Industry
AARON BARR, Technology Advisor, MAKE Consulting
Automotive Light Weighting Opportunities
& Challenges
PROBIR GUHA, Vice President, R&D
- and MIKE SIWAJEK, Director, Research,
Continental Structural Plastics
AND MANY MORE!
For an up-to-date agenda and abstracts, please visit:
http://short.compositesworld.com/CF2013
Source | 3TEX
Work
Work in
in Progress
Progress
Source | 3TEX
3-D woven textiles are stitched through the entire thickness in the center,
but only partially through at the outer edges. This allows portions of the
reinforcement stack to fold at right angles to form the Pi “legs.” The legs
form a slot that receives the shear web, with enough additional space to
allow for adhesive (light green). These preforms are easily co-infused with
the blade shell halves to receive and locate the blade shear web.
3TEX confirmed I-beam test results via static and fatigue testing on 13m
/42.7-ft long commercial-type wind blades.
adhesively bonded to bolster the C-beam. Spacers held the bondline
thickness to 3 mm, ±0.3 mm (0.1 inch, ±0.01 inch).
Sharp says three conventional joint beams and five Pi joint beams
were tested at the Constructed Facilities Laboratory at North Carolina State University (Raleigh, N.C.). The Pi joint beams failed at
an average 12 percent higher load and 20 percent higher deflection
than the conventional beams. That differed slightly from SAMPE
paper data: “Those results included only three of the Pi joint tests
and one of those underwent hysteresis loading. When we tested additional Pi joint cantilever beams without the hysteresis loading, the
averages increased for both load and deflection at failure.”
Notably, the failure in the Pi joint beams resulted from buckling
in the shear web, not failure in the Pi joint. The buckling forced the
vertical legs of the Pi joint outward and, in turn, caused failure in the
adhesive layer. Sharp asserts that increasing the shear web’s buckling
resistance would likely produce an even higher failure load. However,
this is not the case for the conventional joint beams, in which failure
occurred within the adhesive layer first without any onset of buckling.
Not least, the Pi joint beams also cost approximately 15 percent less to
produce (see Table 1, below). Sharp sums up, “Manufacture using coinfused 3-D woven Pi joint preforms requires fewer steps, less fiber,
less resin and less adhesive than conventional joint manufacturing.”
Testing was extended to commercial-type construction of 13m
blades. One blade with each joint type was tested under static load.
Another pair was fatigue tested. Under static load the Pi-jointed
blade failed at a 20 percent higher load and 25 percent greater deflection than the conventional blade. Even more dramatic were the
results of fatigue tests. The test cyclically loaded the blades to 100
percent of the test load (design load plus a factor) for 1 million cycles, then it increased the load by 20 percent for each 200,000 cycles
until failure. The blade with the conventional joint failed during the
160 percent load step after 1.45 million cycles. The Pi joint blade
Conventional Joint (C-beam with L-shaped braces)
3-D Woven Pi Joint
1. Infuse shear web in C-shaped mold
1. Infuse shear web
2. Cut and trim shear web
2. Cut and trim shear web
3. Infuse two L-brace composites in molds
3. Co-infuse spar caps and Pi joint preforms
4. Cut and trim L-brace composites
4. Cure shear webs and spar caps
5. Infuse spar caps
5. Apply adhesive layer to Pi joints
6. Cure spar cap, shear web, and L-braces
6. Insert shear web into top and bottom spar cap/Pi joints
7. Apply adhesive layer to bottom spar cap
7. Cure composite I beam.
9. Apply adhesive layer to one L-brace
10. Attach L-brace to spar cap and shear web
C with L
Pi
11. Cure epoxy putty adhesive
Material Costs
0.17
0.16
12. Apply adhesive layer to top spar cap
Epoxy Costs
0.22
0.19
13. Attach top spar cap to structure
Labor Costs
0.61
0.50
14. Apply adhesive layer to one L-brace
Total Costs
1
0.84
15. Attach L-brace to spar cap and shear web
16. Cure composite I-beam
20
Relative costs of each joint type
Table 1: Manufacturing steps and relative costs for I-beams
that use each joint type.
Source | 3TEX
COMPOSITESWORLD.COM
8. Attach C-shaped shear web
Work in Progress
PI POTENTIAL
Sharp believes the 3TEX-tested Pi joint design could reduce the
weight, cost and need for repairs in wind blades. “By increasing the
ultimate strength and fatigue life, this type of joint should permit
designers to reduce the material in the loaded sections of the blade,
lowering material and manufacturing costs.” Indeed, 80m to 100m
(262-ft to 328-ft) long blades now under development for offshore
turbines might soon benefit from Pi joints (see “Learn More”).
Further, integrating Pi joints into blade construction methods
appears to be a solution because increasing blade lengths tests the
limits of current bond technology. During their discussion of design drivers and expected failure modes in future longer blades at
the 2012 Sandia Wind Turbine Workshop (May 31-June 1, Sandia National Laboratories, Albuquerque, N.M.), representatives
of Bladena (Ringsted, Denmark) pointed out that when the blade
length surpasses 60m/197 ft, fatigue failure in the bondlines and
failure of the shear web become a critical failure mode, a reality
that could be addressed with Pi joints. Bladena, a commercial spinoff of wind energy research institute Risø DTU (Roskilde County,
Denmark), also observed a nonlinear crushing pressure phenomenon that increases in longer blades because they bend more. The
Pi-jointed beams in the test blades exhibited increased stiffness,
which would counter the crushing pressure. Finally, Bladena iden-
tified interlaminar failure in the load-carrying spar caps and shear
web flanges as a risk that increases with blade length. Orthogonally
woven 3-D textiles are inherently resistant to delamination. Thus,
they could improve performance not only in the shear web-to-blade
shell joint but also in the spar cap. Therefore, Sharp believes Pi joint
preforms could provide benefits elsewhere, especially in very large
composite structures, such as those in ships. | CT |
Senior Editor
Ginger Gardiner is a senior editor on the
staff of Composites Technology, based in
Washington, N.C.
[email protected]
Read this article online | http://short.compositesworld.com/G669Zx6I.
Guest columnist David Russell described the multiple advantages of Pi joints
in “The Composites Affordability Initiative, Part I” | HPC March 2007 (p. 9) |
http://short.compositesworld.com/DaWuNQ7U.
One potential destination for Pi joint technology is a U.K.-based Energy
Technologies Institute (ETI) blade design project contracted to Blade
Dynamics (Isle of Wight, U.K.) | “Blade Dynamics receives investment for
new wind blade design” | http://short.compositesworld.com/qC2iQSpC.
CT OCTOBER 2013
surpassed this, withstanding more than 700,000 cycles at the 180
percent load step; it failed after a total of 2.5 million cycles.
21
This automated PreformCenter work cell designed and built by
Dieffenbacher GmbH (Eppingen, Germany) has the capability of
producing preforms at production-rate cycle time (less than
three minutes), using a cutting table, robot arm, binder
application module and draping module. The image below shows
a demonstration preform produced by the work cell.
STRUCTURAL PREFORM
TECHNOLOGIES
EMERGE FROM THE SHADOWS
COMPOSITESWORLD.COM
Not yet in full production, with one
exception, all are aimed at accelerating
composite part manufacture at fast
automotive rates.
22
P
reforms have been used for almost 80 years in infusion
molding processes. For most of that history, however,
the vast majority were made with chopped glass fibers
directed over perforated metal forms in vacuum-forming
processes — think molded transit bus seats, for example. More
recently, engineered preforms have been developed through the
use of automated knitting and weaving machinery. These twoand three-dimensional constructions are increasingly capable
of reinforcing high-performance structural composite parts, but
most have failed to enter the manufacturing mainstream in the
automotive industry due to their perceived high cost, the auto
industry’s change-averse culture and some difficult-to-surmount
engineering hurdles.
During the past decade, however, more stringent fuel economy
and emissions standards have overcome automakers’ resistance to
change. Many are developing structural composites in mass-produced vehicles for weight reduction on the strength of recently developed rapid infusion processes designed to meet high auto build rates.
The good news is that equally fast, cost-effective and sophisticated
engineered preform technologies are being developed in parallel.
“Preforms can be created faster than metal can be stamped, on
the order of several seconds,” asserts Dan Buckley, manager of research and development at American GFM Corp. (AGFM, Chesapeake, Va.). “And contrary to what many in the industry think, preforming can save money when creating parts,” he continues. As a
new generation of engineers comes of age, its members are circling
back to the concept of assembling a complex part’s continuous fiber
reinforcements in a separate, automated process as a way to accelerate composite part processing — with the goal of meeting the auto
industry’s part-per-minute production rate.
Source (both photos) | AGFM
FEATURE: Automotive Composites
To review, a preform is a preshaped fiber form. Its fibers are arranged
in one, two or three dimensions in the approximate shape, contour
and thickness desired in the finished composite part. Traditionally, preforms are made in a separate mold and shaping process,
not in the final part mold. Preforms can be made by spraying
discrete chopped fibers combined with a binder over a form; by
stacking tackified continuous fabric plies; by weaving, braiding or
knitting shapes, or stitching continuous fiber materials; or even
by combining several types of continuous reinforcements (see
“Learn More,” p. 29). Although preforms can be made of prepreg
(see “Prepreg preforms for high-rate automotive apps” under
“Learn More”), the vast majority are dry fiber forms that are subsequently impregnated with resin in a closed mold process, such as
resin transfer molding (RTM) or vacuum-assisted resin transfer
molding (VARTM). Newer, nontraditional preforming concepts
that combine thermoplastic tapes and mats are now in the mix as
well, and several suppliers, including Sigmatex High Technology
Fabrics (Benicia, Calif.), now offer roll goods with integrally woven
three-dimensional structure.
No matter the process, dry preforming fixes the fibers in desired orientations, at a predictable fiber volume, and minimizes the
hands-on
labor required for layup, says Buckley: “It allows you to
h
better
achieve a net-shape part, provides uniformity, part to part,
b
and
an makes the molding process more efficient with the shortest possible
si mold open time.”
The preform type depends on the need. Chopped fiber preforms
with
w randomly oriented fibers have isotropic properties. Although it
is possible to adjust a spray pattern in a way that aligns and orients
fibers to some degree, the load-bearing properties of such preforms
are
ar generally limited by the short fiber length. For better part properties,
continuous fibers are called for, and preforming for higher
performance
structures typically involves engineering fabrics, such
p
as multiaxials.
tion of DRAPETEST, an automated drapability tester, which won
a JEC Innovation Award in 2012. To simulate fabric stress during
preforming, a motor-driven piston moves upward through a flat
circular fabric sample, and the force needed to deform the fabric
is measured. A camera, with appropriate illumination, photographs
the sample at intervals during the piston’s travel while the entire
sample is rotated so technicians can inspect the surface for gaps and
fiber loops or breakage. An optional triangulation sensor is available
to detect larger-scale defects, such as wrinkles, Moerschel explains.
Deformation data and images are displayed on a computer, and image analysis technology developed at the Faserinstitut Bremen (FIBRE, Bremen, Germany) enables automatic fabric fault detection.
DRAPETEST is based on an earlier prototype developed by multiaxial manufacturer SAERTEX GmbH & Co. (Saerbeck, Germany)
under a research program funded by the German government. “The
tester gives manufacturers a chance to detect problems like thickening, creasing or bunching in a multiaxial fabric before the reinforcements are included in a preforming program,” adds Moerschel.
Springback also can cause problems, cautions Buckley. When
an engineering fabric is subjected to pressure in the preforming
Source (both photos) | AGFM
BACK TO BASICS
Today preforms can be quite complex, a fact that multiplies
processing challenges. For example, fabrics must be manipulated to
the desired preform shape, but because glass and carbon fibers don’t
stretch, fiber breakage can cause problems. Conformability, or drapability — how well the fibers of a multilayer fabric shear and change
position during shaping, without losing continuity — depends on
the fabric type, stitch density, stitch tightness, roving or tow density
and whether additional materials (e.g., mats) are added to the
preform. “During the preforming process, fiber orientations change,
which changes the local fiber density and thickness,” explains
Buckley. “Failure to conform to the preform tool creates numerous
process and performance problems.” Determining conformability is
a key issue during preform process design.
“The trend toward production of complex automotive parts
requires noncrimp engineering fabrics for efficiency, but unanticipated fiber shifts during shaping can cause gaps and misalignment,”
adds Ulrich Moerschel of textile testing instrument developer Textechno (Mönchengladbach, Germany). His firm has developed a
way to detect conformability problems with the recent introduc-
Visible in these samples are the wrinkles, bunching and even fiber
breakage that can occur when multiaxial fabrics for preforms are
manipulated and stressed during preforming. Testing is needed to
determine how “conformable” a fabric is or how easily a fabric can be
draped during the preforming process. .
CT OCTOBER 2013
FORMING A UNIFORM PREFORM
23
FEATURE: Automotive Composites
Source (both photos) | AGFM
press, it causes areas of high fiber stress, he explains. Those fibers
have a tendency to relax, or spring back, to relieve the stress, which
results in an improperly sized preform. “The preform tooling must
be designed to compensate for springback, and achieve ‘overforming,’” he says. Overforming refers to pressing the fabric beyond the
actual part dimensions in deep draw areas, on the order of a few
millimeters, so that when the preform springs back slightly, it conforms to the desired part dimensions. “This is why you should not
make preforms in the actual part molding tool,” Buckley advises.
MACHINE AND PROCESS REFINEMENT
A preform demonstrator part is
shown in the mold (above), after
shaping by a forming template.
The photo at right shows the
preform, held in shape by a lightcurable binder, after it was
shuttled into position under highintensity lamps, to cure in 17
seconds, well within automotive
part production cycle times.
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“When springback occurs — because the tool isn’t optimized for
overforming — the preform will be too small.”
Another big consideration is ensuring that the material used
to bind or hold the preform in place during the forming process is
compatible both with the sizing used on the fibers and the resin that
will infuse them. Reported problems include thermoplastic binders that repel thermoset molding resins, resulting in weak resin/fiber bonds, and binders that “wash” and rise to the preform surface
when it is inserted in a hot tool, causing finished part defects. In
recent years binder suppliers have developed binders that crosslink
and cure with the matrix resin. AGFM offers thermoset binders, for
example, designed to work with fiber sizings and to be chemically
compatible with thermoset molding resins.
Equipment and materials suppliers have spent many years developing a variety of preforming methods. AGFM, for one, offers its
fast CompForm process, which employs a proprietary light-curable
binder. Billed as curable in less than 20 seconds, the binder, claims
Buckley, has the potential to cure as quickly as one second, if the
preform shape and complexity permits. The binder works on optically transparent materials, such as fiberglass engineering fabrics
and mats, and it can even cure through some lightweight foams and
hybrid glass/carbon materials.
The binder is produced by Zeon Technologies Inc. (Salisbury,
N.C.) and consists of a resin backbone that can be functionalized
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for compatibility with a wide variety of matrix resins; in addition to (1,230 mm by 760 mm) composite roof segment that could replace
the photoinitiator additive, a viscosity reducer is added to accelerate the portion of the current steel roof that slides backward and stows
wetout. Light from 6,000W visible lamps, such as those provided by in the trunk of the BMW 3 Series convertible.
For the demonstration project, ITA used a multiaxial weft inHeraeus Noblelight Fusion UV Inc. (Gaithersburg, Md.), at a wavelength of 400 to 430 nm, sets the shape. Low-energy light-emitting sertion machine, manufactured by LIBA Maschinenfabrik GmbH
diode (LED) lights are also options as light sources, says Buckley. (Naila, Germany) to make a multiaxial noncrimp fabric (NCF)
Because the binder requires no heat to cure, simple, low-cost tooling specific to the part. The machine was modified to change the fabric
can be employed, without internal or external heating and cooling thickness locally, add z-directional reinforcements, create cutouts
channels and controls. Although the high-intensity, instant-on cur- and affix additional fabrics and mats. The result is a process that can
ing lamps can be expensive, they offer a long working life, and the create, on the fly, a near-net shape that exactly matches the preform
requirements — what Greb calls a “tailored NCF.”
short cure cycles ensure that the per-part energy cost is low.
“If a complete preform can’t be created in a single step on the
A recent prototyping project involved the front bumper for a production car using a biaxial hybrid glass fiber/carbon fiber fabric. The LIBA machine, then additional automated machines are needed,”
fabric was layed in a female preform tool situated on a shuttle table; explains Greb, adding, “In this case, we wanted to integrate fastener
the shuttle then transferred the tool into position under a matching inserts and stringers, so we went to a multistep preforming process.”
air-controlled “forming template” that compressed the layup from A second work cell was outfitted with a CNC cutting table, supplied
above. After shaping, the shuttle moved the tool to a third position, by Assyst Bullmer Spezialmaschinen GmbH (Mehrstetten, Gerdirectly under an array of three high-intensity lamps, for a cure that many), and an industrial robot arm from KUKA Roboter GmbH
took approximately 17 seconds. Buckley explains that the amount of (Augsburg, Germany), with the appropriate end-effector. The work
binder can be varied across the preform, and individual lamps within cell cuts, assembles and places six foam-cored stringers and multiple
the light source can be aimed at specific areas of the preform to op- monolithic padups with embedded aluminum fasteners onto the
timize local stiffness. It is also possible to add customized surface tailored NCF laminate, with a heat-activated thermoplastic binder.
ITA then evaluated the economic feasibility of such a multistep
finishes by inserting thermoformed skins into the preform molds,
preforming cell and process as if it were implemented in a producbacking them with prepreg, and then molding the part.
AGFM says it can design preforming machines with molds and tion setting. An in-house software tool, EcoPreform, was used to
shuttles to meet the production needs for any size of preform. Fur- virtually construct the preforms and project labor and material
ther, CompForm can be modified to accommodate opaque carbon fiber-reinforced materials, reports Buckley, through the use of a
newly developed two-part, quasi-anaerobic
binder, also available from Zeon, that cures
by removing reaction inhibition chemistry
with vacuum and heat.
Preform R&D has been underway for
years at the Institut für Textiltechnik (ITA) at
RWTH Aachen University (Aachen, Germany), notes Christoph Greb, the deputy of ITA’s
Composites Div. His group has delved deeply
into the economics of preforming and how
various approaches will impact a part’s production cost. “Composites offer great potential to reduce automotive structural weight,
yet they’re currently not economically comNorth Coast Composites delivers the complete
petitive with conventional materials, from a
parts solution. For 35 years North Coast Tool & Mold
production point of view, due to the manual
has been an industry leader in the manufacture of
or semi-automated labor involved,” he says.
molds for high performance composites.
ITA’s approach is to combine automated proYou always trusted North Coast to make your molds.
cesses to achieve an economically viable proNow, trust North Coast Composites to make your parts
duction process at its ITA-Preformcenter.
Greb explains that ITA has developed a
The Companies of North Coast
wide range of automated preforming techNorth Coast Tool & Mold Corp.
nologies, and their applicability to largeNorth Coast Composites, Inc.
scale auto production was recently validated
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demonstration part: a 48-inch by 29-inch
25
Source | ITA RWTH Aachen University
FEATURE: Automotive Composites
760 mm (29 inches)
1230 mm (48 inches)
Outer shell
Reinforcements
Stiffeners
Inserts
This
T demonstration composite auto roof component, developed by the
Institut
tit fur Textiltechnik (ITA) at the RWTH Aachen University, was
produced in a multistep automated process that produced a tailored
noncrimp fabric, then robotically formed and placed the foam-filled
stringers and metallic fasteners.
costs. Assumptions included 10-year linear depreciation of all machinery. Greb points out that material costs make up about 95 percent of a preform like the one used for the BMW roof demonstrator.
That said, the data showed that a preform based on a tailored NCF
made by the LIBA machine coupled with robotic placement is much
more efficient to produce than a single-step preform, but because
it requires more capital equipment, the per-piece cost is about the
same. However, the analysis also proved that as the part production
rate increases, the unit cost of the preform goes down.
Although no projects are yet in production with an OEM, Greb
notes, “We are constantly working on further improving the process
by enhancing both single- and multi-process chains.”
A MULTISTEP PREFORM CELL
In 2011, the Fraunhofer Institute for Chemical Technology (ICT,
Pfinztal, Germany) began a long-term collaboration with the
University of Western Ontario (London, Ontario, Canada). The
Fraunhofer Project Centre for Composites Research at Western
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26
opened its doors in November 2012 to develop preforming
processes, reports Vanja Ugresic, a Centre research engineer. A
key element will be a fully automated PreformCenter, designed by
Dieffenbacher GmbH (Eppingen, Germany, and Windsor, Ontario,
Canada) and slated to be up and running in early 2014.
According to Dieffenbacher’s Matthias Graf, managing director
of the Business Unit Forming, the goal for the PreformCenter is a
less than three-minute process cycle, from the unwinding of fabrics
to the finished net-shape preform, syncing the preform cycle time
to the mold cycle time.
The PreformCenter comprises several modules: the first is a CNC
cutting table — more than one table can be included as the project
grows — to cut the plies necessary to make the part preform. “We use a
roll knife, which we believe causes less drag and thus no fiber disorientation,” explains Graf. A robot arm equipped with a vacuum pick-andplace end-effector then transfers the cut plies from the cutting table to
the binder application module, a cabinet containing spray equipment
with nozzles that spray an epoxy-based binder upward onto the preform’s bottom surface. Although the binder is characterized by thermoplastic behavior, it is reportedly compatible with the part resin.
The robotic arm moves the individual plies back and forth to direct
the binder where needed and, Ugresic explains, “As part of the Centre’s research, we will optimize the binder dosing to achieve the lowest
amount of binder possible, on the order of about 3 percent of preform
weight, to minimize any effect of binder on the part quality.” The robot then places the tacky laminate stack on a “draping” module,
which automatically forms the 2-D layup into a 3-D shape — the
most challenging step of the process. Although Dieffenbacher won’t
release specific details about the draping and forming methodology at this point, Graf revealed that after considerable research and
modeling, “we are able to minimize fiber stress during the preforming shaping, and control and influence fiber orientation with our
system.” This, he says, has eliminated preform wrinkling without
sacrificing cycle time.
Ugresic adds that a rigid, heated lower form with an “adaptive”
upper mold shapes the preform at a low compression force. The applied heat ranges from 80°C to 120°C (175°F to 248°F), depending
on the binder. “Achieving wrinkle-free preforms regardless of materials used will be a strong R&D focus at the Centre,” she asserts.
After the PreformCenter is up and running, the Fraunhofer
Project Centre for Composites Research will be available to automotive customers who are interested in trialing preform methods
and materials, says Ugresic. “We are open to cooperate with automotive OEMs, and strategic alliances are already under evaluation.
Depending on the complexity of the project, Dieffenbacher may be
involved as a development partner.”
OVERMOLDING CONTINUOUS REINFORCEMENT
A five-year-old startup, EELCEE AB (Trollhättan, Sweden, and
Lausanne, Switzerland), is marketing a uniquely different approach
to preforms. An automated process cell pulls multiple continuous
fiber rovings or tows from a creel through a series of dies that wet
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Source | EELCEE AB
FEATURE: Automotive Composites
A radical and rapid preforming approach developed by EELCEE AB
(Trollhättan, Sweden) uses fiber tows or rovings that are robotically slung
around a number of fastener points. The resulting skeleton or frame (shown
in white) is then robotically transferred to an injection or compression
molding cell for overmolding with thermoplastic material. The process is
being adopted by automaker Hyundai-KIA for production bumpers.
out the fiber with resin. Then, a robotically controlled layup head
creates an open, tailored 3-D “skeleton,” trademarked QEE-FORM,
by rapidly placing the fiber/resin strands, in any shape or size,
around integral metallic bushings or fastener points. The resulting
QEE-FORM frame is then robotically placed in either an injection molding machine, where it is overmolded with thermoplastic
resin, or in a compression molding press, where it provides addi-
tional reinforcement for glass mat thermoplastic (GMT) or sheet
molding compound (SMC). “Our integrated preform processing
technology, trademarked QEE-TECH, enables the production of
lightweight, structural thermoplastic composite parts at a high rate
and at lower cost than legacy materials,” claims company founder
Dr. Jan-Anders Månson. “The tailored preforms allow a shorter and
faster path from fiber and polymer to finished parts.” Cycle time
is 45 to 90 seconds, in the range of the part forming process that
follows. Woven or unidirectional fabrics, in prepregged form, can
be incorporated into the QEE-FORM preform and easily fixed in
place with an application of heat, with tailored structural properties.
“This technology integrates the advantages of conventional thermoplastic and compression molding along with those of continuous fiber reinforcements,” Månson sums up. Targeted applications
include structurally loaded auto parts, such as bumper beams, seat
structures and front-end module carriers. EELCEE develops a concept and design in consultation with the OEM or end-user, then
produces the QEE-FORMs at its production facilities.
COMPLEX PREFORMS ENTER PRODUCTION
Automakers have finally begun to take notice. EELCEE won a JEC
Innovation Award at the 2013 JEC Asia event in Singapore for its
work with Hyundai-KIA Motor Group and molder Hanwha (both
based in Seoul, South Korea) on a new thermoplastic bumper
system. A 3-D QEE-TECH tow framework is overmolded with
GMT in a compression molding process. “The QEE-TECH applica-
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tions are, in general, about 30 percent lighter and nearly 20 percent
less costly than the legacy metallic version and offer much better
collision performance,” says Månson. The joint development began
in 2010, with the design based on modeling, simulation and full
prototype testing. The bumper meets the Insurance Institute for
Highway Safety (IIHS) 10 kmh (6.2 mph) full barrier requirement
and is slated to launch on two passenger car models in 2014.
Another award-winner is the Part via Preform (PvP) process
developed by Toho Tenax Europe GmbH (Wuppertal, Germany),
which won an AVK Innovation Award at Composites Europe 2013.
The one-step “bobbin to preform” process uses Tenax carbon fiber combined with a binder resin to form a “binder yarn,” which
is chopped in an automated process and combined with UD carbon tapes to form complex preforms for high-pressure resin transfer molding, achieving an acceptable tradeoff between mechanical
properties and cost, says the company.
Elsewhere, BMW (Munich, Germany) has put in place perhaps
the most complex preforming process to date: the automated preform lines at its Dingolfing and Leipzig plants are currently producing the all-carbon Life Module body for the i3 electric car. Carbon
multiaxial fabrics with binder are preformed in a multistep process.
The fabrics are assembled in Wackersdorf, Germany, from carbon
fibers produced at its Moses Lake, Wash., facility operated by SGL
Automotive Carbon Fibers (a joint venture between BMW and
Weisbaden, Germany-based SGL Group). According to published
sources, the Life Module comprises 150 separate pieces that are
preformed, with heat (in some cases, ultrasonic energy) to set the
binder, and then resin transfer molded in a high-pressure press.
Concludes Buckley, “Preforming is extremely underappreciated.
It’s actually more important than the molding process, but it has so
often been overlooked.” Given the current auto lightweighting push,
new preform technologies appear to be reaching maturity. | CT |
Technical Editor
Sara Black is CT’s technical editor and has
served on the CT staff for 14 years.
[email protected]
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Read “Prepreg preforms for high-rate automotive apps”online | http://short.
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See previous CT coverage of preforming technologies in the following:
“High-volume preforming for automotive application” | CT October 2008 (p.
52) | http://short.compositesworld.com/3QQtyZX7.
CT’s sister publication High-Performance Composites has examined preform
approaches within the past year in the following:
“Tailored Fiber Placement: Besting metal in volume production” | HPC
September 2013 (p. 54) | http://short.compositesworld.com/7QEhsvZ0.
“Rapid layup: New 3-D preform technology” | HPC September 2012 (p. 40) |
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FEATURE: Wind Energy Update
Wind
Blades
PROGRESS &
CHALLENGES
Despite double-digit wind energy industry growth, turbine blade manufacturers and
materials suppliers acknowledge a pressing need to reduce costs and innovate.
T
Source | Siemens
he past year was exceptional for the world wind energy
market, as wind-generated electricity continued to increase
its share of the overall electric power supply base. The global
wind power industry grew about 16 percent in 2012, adding 45
GW of new capacity. This increased total capacity to 285 GW, or
about 2.62 percent of the world’s electricity, according to statistics
published by online energy market news aggregator TheEnergyCollective.com. In the U.S., 6 GW of new capacity was installed in
2012, 19 percent more than in 2011. Wind turbines now account
for roughly 3.4 percent of all electricity generated in the U.S. With
the Jan. 1, 2013, extension of the federal Production Tax Credit, the
U.S. is expected to add 5 GW of wind-generated electricity this year.
Despite the ongoing expansion of wind power, the wind energy
industry’s mandate to innovate has never been greater. Its ability to
compete with other renewable and nonrenewable sources of energy
and the continued growth and profitability of turbine manufacturers and suppliers depend on it. Areas of concern include better ways
to enhance not only the mechanical and aerodynamic performance
of turbine blades but also their weatherability and resistance to environmental elements. It is also incumbent on the industry to explore
ways to reduce the radar signature of wind farms — an issue that has
resulted in delays or cancellations of some farm installations. Last,
there is a sense of urgency about mitigating the cost of manufacturing, installing and metering wind turbines in anticipation of what
many experts predict will inevitably be
a subsidy-free, level energy playing field.
PUSHING PAST THE
EFFICIENCY PLATEAU
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If the rotors of a wind turbine are not
turning, the turbine is not producing
electricity and its owners are not making
money. That fact feeds the perception
among critics that wind cannot compete
with on-demand power sources, such
as fossil fuels, nuclear and hydro. Thus,
one rationale for longer rotor blades is
that the longer the blade, the greater the
amount of time a turbine will spend in
service under variable wind conditions,
a metric known as capacity factor.
30
Pictured here is one-half of the mold
P
Siemens AG (Erlangen, Germany) is using to
build rotor blades for what the company says
will be the world’s largest turbine, the SWT6.0-154. Its 75m/246-ft balsa-cored glass/
epoxy blades will be molded in one piece to
eliminate seams and bonded joints. A Danish
energy provider is planning to install about
300 of the turbines off the British coast when
testing is complete.
Chicago, Ill.-based Invenergy is installing three off
GE’s new 2.5-120 turbines at the Goldthwaite Wind
Energy facility presently under construction in Mills
County, Texas. The largest in GE’s line, they feature wind
blades 60m/197-ft long and a new, onboard short-term
battery storage system, which enables energy storage
during peak generation.
Source | GE Wind Energy
Source | GE Wind Energy
Keith Longtin, general manager, wind product line, for GE’s
renewable energy business, says the company has increased the
capacity factor of its current turbines to more than 50 percent, up
from roughly 35 percent 10 years ago. Longtin reports that GE
sold more than 1,000 of its 100m/328-ft diameter 1.6-MW 1.6-100
wind turbines in 2012 — all installed in the U.S. This turbine has
a capacity factor of roughly 53 percent. The turbine’s 48.7m/159.8ft blades are E-glass/epoxy sandwich constructions with a hybrid
core that comprises balsa wood and PVC and SAN foams. Each
blade weighs approximately 10 metric tonnes (22,000 lb), has a
root diameter of 2.5m/8.2 ft and a chord width of 3.5m/11.5 ft.
More recently, Invenergy (Chicago, Ill.) became the first company to purchase GE’s new 2.5-120 series turbine. The turbine is
equipped with 60m/197-ft long blades and has a capacity factor of
more than 50 percent in low-wind conditions. Invenergy purchased
three of the 2.5-MW turbines, which will be installed as part of
Goldthwaite Energy Center, an 86-turbine facility under construction in Mills County, Texas. GE says the turbine is the first to integrate short-term battery storage and software that enables power
producers to store short-term surges in power during peak wind
conditions. This onboard system eliminates the need for more costly
offline, farm-level battery storage systems.
Longtin reports that one of the company’s strategies for reducing variability and costs in the ramp up to bigger blades is a standardized design and manufacturing process, which facilitates scalability of composite layups. The company also collaborates with its
suppliers to find ways to enhance automation. For example, one of
the company’s suppliers, TPI Composites, which manufactures rotor blades for GE’s turbines at its plant in Newton, Iowa, reports
using hydraulic power hinges to assemble blade halves. The hinges
have eliminated the need for flip fixtures for skin demolding, resulting in significant reductions in assembly time. TPI manufactures
blades using the Seamann Composites (Gulfport, Miss.) Resin Infusion Molding Process (SCRIMP), in which feed lines, vacuum lines
and embossed distribution channels are integrated into a reusable
vacuum bag to reduce setup time and improve process repeatability.
DESIGN FOR MANUFACTURE
Building ever-larger rotor blades using the same or similar production methods and materials is a strategy now subject to the law of
diminishing returns: The increase in the weight of, and loads borne
by, longer turbine blades outpaces the increases in power capacity.
Turbine manufacturers, therefore, are vigorously investigating optimized designs, lighter materials and more efficient manufacturing
processes to reduce blade weight and cost.
Custom molder Molded Fiberglass Cos. (Ashtabula, Ohio) manufactures
C
spinner nosecones, which fit over the rotor hub, by vacuum infusion from
E-glass and polyester. Company VP Carl LaFrance says greater collaboration
between suppliers and blade manufacturers is a must if the industry is to
reduce system costs and compete with other sources of power.
CT OCTOBER 2013
BETTER DESIGN AND
31
FEATURE: Wind Energy Update
Siemens AG (Erlangen, Germany) is building what is purported
to be the world’s largest wind turbine, the SWT-6.0-154. Each of its
three B75 blades measures about 75m/246 ft in length. Fabricated
as a single cast part, comprising glass, epoxy and balsa wood, the
blade is molded via the company’s patented and trademarked IntegralBlade process. The seamless blade has no bonded joints — weak
points that could crack or separate, exposing the joint to water ingress and accelerated weathering. Additionally, a weight savings of
about 20 percent, compared to conventionally produced blades, is
achieved by incorporating a specially designed blade profile, shaped
to maximize the rotor capacity factor at a variety of wind speeds. The
turbine has a cut-in wind speed of 3 to 5 m/sec, produces nominal
power at 12 to 24 m/sec and has a cut-out wind speed of 25 m/sec.
It is part of the company’s D6 platform, which replaces the gearbox,
coupling and generator with direct-drive technology that eliminates
about 50 percent of wear-prone and geared parts. The reduction in
associated maintenance costs is especially advantageous for offshore
applications. Siemens is testing the B75 blades on a prototype 6-MW
turbine at Denmark’s Osterlid test station. After testing is complete,
power supplier Dong Energy (Fredericia, Denmark) plans to pur-
chase and install about 300 SWT-6.0-154 turbines off the British
coast, according to a recent press release from Siemens.
Meanwhile, Kolding, Denmark-based LM Wind Power’s
73.5m/240-ft blades were installed on Alstom’s (Levallois-Perret,
France) Haliade 150-6MW wind turbine in Carnet, France, this past
year, and the company has plans to open a blade manufacturing plant
in Cherbourg, France, and begin production of the blades there by
2016 (see “Learn More,” p. 35). The glass/polyester blades feature the
company’s SuperRoot design, which supports blades that are up to
20 percent longer without an increase in root diameter. Additionally, in 2012, LM Wind Power extended its GloBlade line of ultraslim
wind turbine blades to 3-MW turbines. Originally introduced for
the 1.5-MW segment, the GloBlade replacement blades are designed
with “plug-and-play” features that make them compatible with a variety of turbine platforms and aerodynamic configurations. The new
3-MW line includes 58.7m and 61.2m (192.6-ft and 200.8-ft) blades,
which the company says can improve annual energy production by
as much as 14 percent, compared to the standard blades they replace.
Molded Fiber Glass Cos. (MFG, Ashtabula, Ohio) custom molds
blades and a variety of parts for wind turbines. For example, the
Source | GE Global Research
A DIFFERENT TYPE OF BLADE?
A potential paradigm shift in wind turbine blade manufacture is afoot at
GE Wind Energy (Niskayuna, N.Y.). The company’s global research arm,
along with Virginia Polytechnic Institute & State University (Blacksburg,
Va.) and the National Renewable Energy Laboratory (Golden, Colo.), recently secured a three-year grant under the U.S. Department of Energy’s
Advanced Research Projects Agency to investigate the use of resin-
impregnated architectural fabrics as a substitute for conventional composite laminates in the construction of wind blade skins. In this design,
as envisioned, fabric is stretched or “tensioned” around a spaceframe of
stamped metal ribs.
The fabric is impregnated
with resin to make it impermeable
to wind and water intrusion. Wendy Lin, GE’s principal engineer
and lead on the project, declines
to identify the fabric; however,
she stresses that the resin is nei-
COMPOSITESWORLD.COM
ther an epoxy nor a polyester, but
32
a “rubbery,” compliant material
Wendy Lin, a principal engineer
W
E Global Research, wraps resinat G
GE
impregnated fabric around a prototype wind blade segment. The inspiration for GE’s tensioned-fabric
concept was a similar fabric used as
the cover of an outdoor café (left) at
GE’s John F. Welch Technology Center
in Bangalore, India.
that allows GE to assemble the
blade in large segments without risk of the blade buckling.
Lin says the impetus for the project was an internal directive at GE
and eliminate the logistical problem, and associated costs, of transporting long blades to turbine sites. Instead, the blade components could be
to reduce the cost of manufacturing wind blades by 50 percent. If the
shipped in container kits and assembled on site. “We still have a ways
fabric is successful, GE claims the new blade design could reduce blade
to go to prove it out, however,” Lin admits. “Size constraints imposed by
production costs by up to 40 percent and put wind energy on equal
current technology require thinking outside the box.” But, she says, the
economic footing with fossil fuels, without government subsidies. Lin
concept could pave the way for blades as long as 130m/426.5 ft, mak-
says the design would permit automotive-type precision and tolerances
ing them suitable for harvesting wind in moderate wind locales.
company manufactures a spinner nose cone, which fits over the global communications at LM, says the barrier technology will be
windward side of the rotor hub, from E-glass fabric and polyester for available, initially, only on blades produced by LM Wind Power.
a major wind turbine manufacturer. Carl LaFrance, MFG’s VP of reAnother option, Arkema Inc.’s (King of Prussia, Pa.) KYNAR
newable energy products, cites the need to reduce wind energy’s cost PVDF-acrylic hybrid emulsion coating, has been used for more
per kW-hr and to make investments in material and process R&D. than 30 years as an architectural weather coating on exposed metal
“We don’t have a full understanding of how blade design, materi- in large commercial buildings and public structures. The original
als and manufacturing processes affect system costs,” says LaFrance, solvent-borne emulsion requires baking at temperatures up to
“so we don’t have any idea about how much cost we could potential- 200°C/392°F to cure. However, the company introduced a waterly take out.” He believes that will require more upfront collaboration based version of KYNAR, in both thermoplastic and thermoset forbetween custom molders and turbine manufacturers, but adds, “it’s mulations, which is curable at room temperature and can be applied
a conversation not all customers are willing to have because of the to a variety of composites.
competitive nature of this business.”
LaFrance specifically earmarks the
need for tougher matrices, and he notes
that early testing and prototype work with
polyurethanes appears promising. “Polyurethanes have much better fatigue properties than either polyester or epoxy,” he
A N NIVE
RS
contends. LaFrance also reports that some
materials suppliers are researching methHPC
Visit TFP at SAMPE Tech 2013
ods to make vinyl ester a tougher material.
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AR
20
Y
Advertiser
AND DE-ICING CAPABILITY
As blades get longer and blade tips reach
greater speeds, resistance to wind-driven
rain, ice, sand and salt is a key performance
criterion, especially along the blade’s leading
edge. When wind-driven particulate strikes
a blade spinning as fast as 60 m/sec, there
is the potential for damaging shear forces in
the first laminate layer of the edge. Leadingedge erosion reduces power output, which
results in significant revenue loss for wind
farm operators.
To counteract erosion, LM Wind Power
recently introduced a new protective coating technology, LM ProBlade Collision
Barrier. The company claims the coating
can improve erosion resistance along the
leading edge by up to 20 times, compared
to standard barrier coatings already in use.
The coating system comprises a primer
and an aliphatic-based, solvent-free, twocomponent, highly elastic polyurethane
topcoat. LM says results of independent
testing on prototype blades shows the coating lasts about twice as long as leading-edge
thermoplastic polyurethane tape. Tape produces aerodynamic drag, and LM estimates
that eliminating it can enhance the average
annual energy production of a turbine by 2
percent. The company began serial production of the coating in the second quarter of
2013. Lene Ri Ran Kristiansen, manager of
Surface Engineering
for Composites
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33
FEATURE: Wind Energy Update
COMPOSITESWORLD.COM
Kurt Wood, group leader of KYNAR PVDF coatings R&D, reports
that the company has been working with researchers at North Dakota
State University (NDSU) to evaluate the performance of paints formulated with the water-based thermoset and a hybrid resin when they are
applied on typical glass/epoxy laminates as a possible all-purpose leading-edge and weather-resistant coating. In the thermoset formulation,
hydroxy-functional monomers are incorporated in the acrylic portion;
the hybrid resin is combined with commercially available water-dispersible polyisocyanate crosslinkers to produce a two-part urethane.
The resulting crosslinked polymer in the applied coating is structured
as a bi-continuous network of fluoropolymer and acrylic urethane.
34
The standard rain erosion test, first developed for helicopter
blades, spins blades on a fixture at a high speed through simulated
rain. This test is very expensive. Arkema, therefore, is working with
NDSU to develop an alternative test method that keeps the part stationary and uses a wind tunnel to accelerate water droplets into the
part at high speed. This method will be used to test the rain erosion
of blades coated with KYNAR-based paints. The company will be
presenting preliminary test results at several wind energy conferences this year. Wood says the company also has done studies that suggest the hybrid resin may have superior long-term erosion-resistance
and ice-shedding properties compared to a number of commercial
urethane coatings that are currently in use.
To address leading-edge erosion, 3M’s
Renewable Energy Div. (St. Paul, Minn.)
now offers Wind Blade Protection Coating W4600. The product, which was introduced to the market in May, is a two-component polyurethane coating designed for
“Service is my top
application via brush or by casting at the
priority; you can depend
OEM facility. 3M also offers Wind Tape
on me to get you the
right materials — on time.”
8608 and 8609 for erosion control at the
Tony Seger, Composites One
leading edge. The pressure-sensitive tape
Warehouse Team
is UV stable and puncture resistant, and
it can be die- or plotter-cut to conform to
complex 3-D shapes.
Currently GE Wind Energy employs
process controllers on most of its wind turbines to manage ice buildup on the turbines’
rotor blades. When the controller detects
imbalances in the rotor as a result of ice
buildup, it adjusts the rotor speed to allow
continued safe operation, or it shuts down
the turbine if ice buildup becomes too exProduct | People | Process | Performance
treme. But Longtin reports that GE also has
conducted field testing of a “nanoparticle,
ice-phobic coating” on its 1.6-MW turbine
blades, with encouraging results. “We are
There’s not just one thing that sets us apart at
going to announce the results later this year
Composites One, there are thousands – of PRODUCTS that is,
but we think the technology has promise,”
including the widest range of raw materials from
more than 400 industry-leading suppliers. We stock everything
says Longtin.
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REDUCING WIND TURBINE
supplies helping your operation stay productive.
RADAR INTERFERENCE
You’ll get them quickly, thanks to our nationwide network
As wind farms proliferate, a concern about
of locally based distribution centers. You’ll also receive the
turbine radar interference has, in recent
unparalleled support and value-added services that
years, prompted aviation, weather, military
only a market leader can provide.
and marine operations to contest proposed
wind turbine installations. The Union of
That’s the power of one. Composites One.
Concerned Scientists (Cambridge, Mass.)
estimates the issue has delayed the installation of as much as 6 to 9 GW of potential wind energy production. In a white
800.621.8003 | www.compositesone.com | www.b2bcomposites.com
paper that addresses radar interference
from wind farms, the group recommends a
See us at booth B8 during SAMPE Tech 2013 in Wichita, KS, Oct. 21-24.
number of mitigation measures, including
upgrades to the aging, long-range radar infrastructure, modificawithout subsidies, wind energy is competitive, or nearly competitions to wind farm design to reduce radar cross-section and the use
tive, with traditional energy sources, including coal and oil. Onof “gap fillers” in radar coverage.
going materials and manufacturing innovation will help push this
Turbine manufactures also are investigating technologies to reimportant end market to wider, and permanent, acceptance. | CT |
duce the intrinsic radar signature of wind blades. Vestas Wind Systems A/S (Aarhus, Denmark) is reportedly researching the use of
Contributing Writer
a stealth technology, similar to what is used in military aircraft, to
Michael R. LeGault is a freelance writer
reduce a turbine’s radar signature. The company has built a numlocated in Ann Arbor, Mich., and the forber of experimental wind blades that comprise two layers of glass
mer editor of Canadian Plastics magazine
fabric printed with a special “ink.” The radar signal passes through
(Toronto, Ontario, Canada).
the first layer and is effectively trapped between the two layers. [email protected]
cording to online reports, the technology
works, but the cost could be prohibitive —
especially considering the market pressure
on turbine manufacturers to reduce, not
raise, costs. Further, a turbine completely
undetectable to radar would pose a hazard
to aircraft flying in the vicinity of a wind
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farm. The trick, which Vestas is attempting
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Elsewhere, GE Wind Energy is taking a
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“commercial radar-absorbing materials”
to rotor blades, which have subsequently
been tested on turbines and were shown to
be capable of reducing radar interference.
“We are using materials that you can purchase off-the-shelf and staying away from
more exotic materials used in the defense
industry,” says Longtin. “If the industry
were to move to requiring a blade producing less radar interference, we think we
have some technology that we can draw
upon that could help.”
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CT OCTOBER 2013
thermal stability and fatigue strength,
and will not absorb water. These
35
INSIDE MANUFACTURING
Maximum
thrills
MINIMAL
TOOLS
Water slide manufacturer’s disastrous fire loss opens door to a closed molding process
that reduces the number — and cost — of production molds, promising future gain.
M
tooling costs can be greatly reduced by producing parts of multiple
sizes from a resizable mold and a single, reusable vacuum bag.
Built according to design parameters specified in ASTM F237608, “Standard Practices for Classification, Design, Manufacturing
and Operation of Water Slide Systems,” SplashTacular’s 360Rush
slide consists of a 58-ft/17.7m high tower and two curved, enclosed
tubes or flumes, approximately 120 ft/36.6m in length, that feed into
a “bowl” at the bottom. Two riders enter the slide through trap doors,
descend at speeds up to 40 mph/64 kmh, and then emerge into the
bowl where they spin around its walls before they
splash into about 8 inches/203 mm of water at the
bottom. The ground-level footprint of the slide is
SplashTacular’s 360Rush,
approximately 80 ft by 80 ft (24.4m by 24.4m).
installed at the Spring Valley
SplashTacular had developed the 360Rush
Beach amusement park at
design
and received a contract to build the slide
Blountsville, Ala. Its tower and
two enclosed composite flumes
before a fire destroyed its facility in Garnett, Kan.,
feed riders into a “bowl” at the
where the company’s fiberglass water slide combottom, where they spin around
ponents had been produced. SplashTacular had
the rim of the bowl (lower
already contracted with JRL to build the molds
right) before splashing
for the slide. Facing a tight deadline, SplashTacuinto about 20 inches of
lar hired JRL to make the parts, too, rather than
standing water at
going through the time and expense of shipping
the bottom.
tooling to a third-party fiberglass manufacturer.
Not unfamiliar with part production, JRL offers
prototype and first-article production as part of
its package of standard toolmaking services.
akers of amusement park equipment and composites
manufacturers have had a long association, the beginnings
of which go back at least 50 years to the days when fiberglass began to replace metal and wood in cars and seating for thrill
rides, as well as park benches, decorative accessories and other park
features. Based on one-off and limited-run parts, amusement park
jobs have high per-part tooling costs. But on a water slide project
recently completed by SplashTacular (La Quinta, Calif.), Cape
Coral, Fla.-based tooling supplier JRL Ventures demonstrated that
36
Source (both photos) | SplashTacular
TOOLING VENTURE
MULTI-SIZE CAPABILITY
Several years before the 360Rush project, SplashTacular and JRL
had conferred about the possibility of using a modified closed
cavity bag molding (CCBM) process that employed partial molds
in slide sections. Partial molds are designed with moveable flanges
or blockers that can be repositioned, enabling the company to make
parts of more than one size from a single mold. JRL had experience
producing some first-article parts with CCBM, which uses a rigid
A-side mold and a silicone or elastomeric bag on the B side, but had
not tried it with a partial-mold configuration.
“One of the problems in the past when we tried to use a closed
molding process, such as light RTM, is that we had to build a full
mold for every part, which gets expensive,” says Jeremy Wilson, senior project engineer at SplashTacular. “We just felt there had to be
a way to make this happen.”
Wilson credits JRL with make partial molds compatible with
the CCBM process by developing a way to use a single reusable bag
with a partial mold to produce parts with different lengths. One of
the partial molds, for example, makes slide flume sections that are
90, 42, and 37.5 inches (2,286, 1,067 and 953 mm) long. The length
of the bag is dictated by the longest part. The blocker is moved to
shorten the part length. The challenge, then, was to get the bag to
seal and hold a vacuum around the blocker and conform to the
blocker’s shape. “We had to experiment,” says Kevin Long, project
manager at JRL, who reports that they “found a way to make the
blocker without any sharp angles or bends so when you pull a vac-
Silicone bags for the project were made directly off the tool, rather than
S
ffrom wax inserts or a hand-layed model. The technique worked well with
sslide molds because the parts have large and open shapes and are made
Source | SplashTacular
with identical ply schedules.
w
uum and begin to infuse that section, the bag pulls down and seals
without inflicting damage.” The rubber seal around the flange of the
entire bag holds the vacuum in that section, and the inherent elasticity of the silicone conforms to the shape of the blocker.
Ultimately, the experiment yielded significant savings in tooling
cost. The slide’s 134 parts were produced with 12 full molds and three
partial molds. Notably, the three partial molds, which formed sections
of the slide’s flumes, accounted for more than half of the total parts.
After the final design was approved and the partners were satisfied that their new tooling strategy was viable, tool build was initiated with the manufacture of plugs. CAD data was imported into a
5-axis CNC machine for cutting plug components, the majority of
which were rough cut, with an undercut shape, out of low-density
expanded polystyrene supplied by Carpenter Co. (Richmond, Va.).
The plugs were sealed with a proprietary resin and coated with ITW
SprayCore’s (Clearwater, Fla.) SprayCore 4500, a sprayable, syntactic vinyl ester. The cured syntactic offers a hardened layer of material
that, Long says, exhibits low shrinkage and is easy to machine. After
the plugs were milled, their surfaces were dry- and wet-sanded to
a 400-grit finish.
FFiberglass toolmaker JRL Ventures (Cape Coral, Fla.) developed a method
oof using a single reusable bag with a partial mold (below) to produce
pparts of different lengths by means of a moveable flange or blocker
((colored black). This partial mold can produce slide flume sections that
aare 90 inches, 42 inches and 37.5 inches in length.
Source | SplashTacular
CT OCTOBER 2013
JRL is a subsidiary of Cape Coral-based Marine Concepts. Engineering director Kevin Long says the company has been seeking to
grow its share of business in the amusement park market over the past
five years. After attending shows, such as the International Association
of Amusement Parks and Attractions (IAAPA) in Orlando, Fla., Long
says the company realized it couldn’t compete in molds for small, intricate parts made primarily in Asia. It did, however, perceive an opportunity in the water park segment, which usually entails the production
of much larger parts. SplashTacular’s 360Rush represented JRL’s first
significant multimold contract in this market.
JRL primarily used NX CAD software, supplied by Siemens
PLM Software (Plano, Texas), to finalize the slide design, surface
part sections and fair section mating surfaces and edges. Finite element analysis (FEA) was performed on CAD models of the complete slide as part of the design process. SplashTacular used NASTRAN FEA software to conduct and analyze a ride simulation of
two people descending through the slide and into the bowl. The
main program inputs were the heights, weights and proportions of
the riders. SplashTacular engineers evaluated the simulation to verify that the linear motion of each rider stayed at or below a threshold
speed at specific locations on the slide. Rider speed and location
within the flumes were assessed to ensure there is no chance two
riders will collide as they enter the bowl. The contribution of slide
design to any anomalies in rider mechanics during the simulation
was assessed by SplashTacular engineers, resulting in further modification of the CAD model. Additional NASTRAN simulations and
iterations continued until an acceptable design was achieved.
37
INSIDE MANUFACTURING
2 Technicians initiate part production by pulling
a vacuum of 23 to 28 psi on the bag.
3 The mold is infused with an ISO dicyclopentadiene resin that contains a blended
catalyst. The resin enters through two ports
at the top of the bag.
4 Filling the mold usually takes 12 to 15
minutes, depending on the size of the part.
5 Once the mold is filled, injection lines are
clamped to maintain the vacuum and the
curing process begins. The cured part is
allowed to cool on the mold.
6 The part is pulled from the mold, and its
backside is ready for gel coat.
Source (all step photos) | SplashTacular
1 After application of the gel coat, a single layer
of 18-oz woven roving is layed up on the mold
and the silicone bag is positioned and secured
over the cavity and flange.
hold a vacuum during infusion. An added challenge to the tool design-and-build phase of the project — for partial, split and standard
molds — was the complex three-axis part curvature along the length
of most slide sections. This complicated the tool design and build, as
well as part connectivity. “The bolt line is not simply a vertical flange,”
Long points out, “so we had to take care during CAD modeling to
ensure all the parts mated 90° to the mating surface.”
MULTI-USE CAPABILITY
For the vacuum bags, SplashTacular and JRL used sprayable grades
of silicone supplied by a number of companies. Approximately
0.125 inch/3.18 mm thick, the silicone bags are more expensive than
traditional disposable bag materials, but their upfront cost is mitigated by the fact that they are reusable. JRL further reduced the perpart bag cost on the 360Rush project by pulling the bags directly
off the tools, rather than from wax inserts or a hand-layed model.
Although this technique is not always advisable, it worked well with
the slide molds because the parts have large and open shapes and
are made with an identical ply schedule. “In a structure with cores
you would not want to build the bag off the mold because you’d
create wrinkles,” he warns.
SplashTacular uses in-house resin blending equipment to produce its own gel coats in 180 colors. But because of the blaze, blue
and green gel coats (for the inner and outer surfaces of the slide and
bowl, respectively) were custom mixed to SplashTacular’s speci-
CT OCTOBER 2013
After polishing, each plug cavity was prepped with mold release
and then coated with Polycryl Corp.’s (Oakland, Tenn.) Diamondback Y-501 orange gel coat. Next, a layer of 1.5-oz glass mat, supplied by Composites One (Arlington Heights, Ill.), was hand layed
over the cured gel coat and wet-rolled with Polycryl’s Earthguard
EG2500 vinyl ester tooling resin. Two additional layers of 1.5-oz
mat were laid and wet rolled over a two- to three-day period. Finally, a layer of Earthguard EG3000 high-temperature vinyl ester resin,
averaging 0.5-inch/12.7-mm thick, was applied over the glass mat
and allowed to cure at ambient temperature to yield molds ranging
in thickness from 0.375 inch to 0.75 inch (9.5 mm to 19 mm). The
cured, demolded tool surfaces were wet sanded to a 600-grit finish and then power buffed using a three-step compounding process.
The blockers for the partial tools were formed by hand laying six
consecutive layers of 1.5-oz glass mat, each of which was wet rolled
with Earthguard EG2500. After the finished tools were supported
with steel framing, they were production ready.
One of the unique aspects of manufacturing the slide was the high
percentage of split or captive-shape tools. Of the 15 tools produced,
11 were split, including the three partial tools. “Because of the negative draft angles and undercut on many of the slide sections,” Long
explains, “you couldn’t remove the part without removing part of the
mold.” The split molds, therefore, typically feature three or four sections contained or cradled in the tool’s steel-reinforced frame. Rubber
gaskets along the seams of the split sections ensure that the molds
39
INSIDE MANUFACTURING
fications by Ashland Performance Materials (Dublin, Ohio) and
shipped direct to JRL.
After the gel coat application, a single layer of 18-oz,
0.25-inch/6.35-mm thick woven glass roving was layed up, and the
bag was positioned over the cavity and flange. A fiberglass ring was
clamped to the bag flange, and a vacuum of 23 to 28 psi (1.59 to 1.93
bar) was drawn. The layup was infused with an ISO dicyclopentodiene (DCPD) resin with a blended catalyst supplied by No. Kansas
City, Mo.-based CCP Composites. The mold fill times varied by part
size but generally fell in the range of 12 to 15 minutes.
“Mold filling for a specific part with CCBM is metered by pump
strokes quite accurately,” says Wilson, noting that some of the larg-
er parts require up to 100 strokes to fill. The largest part, a section
of the bowl, was approximately 115 ft2/10.7m2, and the smallest was
about 24 ft2/2.2m2. Cure, at 108°F/42°C, was complete in about one
hour, compared to eight hours for a typical open-mold manufacturing method. The parts, on average, were about 0.25-inch/6.4mm thick.
“One of the benefits of CCBM compared to open molding is a lot
less post-mold finishing,” Wilson says, reporting that the slide parts
required minimal trimming in the flange areas and only touch-up
sanding at the injection ports. The final step in the process was hand
spraying the B side with the gel coat used on the A side.
SplashTacular was keen to tap the benefits of JRL’s CCBM process but did not want to sacrifice surface
quality on the flume’s B side, which is visible to park visitors. (In the bowl, the A
side is visible.) Ultimately, Wilson says, his
team was pleased with the B side, reporting that the parts had “some typical orange
peel” but no fiber print through. Long says
JRL conducted preproduction trial-anderror runs with different fabrics to obtain
the smoothest possible B-side finish in
production.
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40
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The tooling was finished in May 2011, and
JRL molded the 134 parts for the slide
over a four-week period. The 360Rush was
operational at Spring Valley Beach amusement park in Blountsville, Ala., in time for
the July 4 weekend.
Since then, SplashTacular has moved its
manufacturing to a new site and molded
two slides for Hawaiian Falls, The Colony,
near Dallas, Texas, with the same molds
and bags used for the 360Rush. And JRL
is seeking to solidify its market position by
developing a closed-mold process that will
provide a better B-side finish. | CT |
Contributing
Writer
Michael R. LeGault
is a freelance writer
located in Ann Arbor,
Mich., and the former
editor of Canadian Plastics magazine
(Toronto, Ontario, Canada).
[email protected]
1-866-319-8827 or visit us at
AOC-Resins.com today to
learn more.
compositesworld.com
Read this article online |
http://short.compositesworld.com/vqH7gkns.
Applications
Applications
The city of Austin, Texas, undertook a complex wastewater project
that included a new 3.9-mile/6.3-km wastewater tunnel. Because the
project was designed to increase wastewater capacity in the downtown district and facilitate residential and business growth in the
area, city officials knew that it would be important to control odor
in and around the tunnel. ECS Environmental Solutions (Belton,
Texas) was contracted to provide odor control equipment and relied
on Vipel vinyl ester resin from AOC Resins (Collierville, Tenn.) for
more than 1,000 ft/305m of fiberglass ductwork and accessories.
The ductwork would range in diameter from 12 to 72 inches (305
to 1,829 mm). Approximately half of it would be buried below grade
and would have to withstand thousands of pounds of high-density
loads from vehicle traffic. Additional project elements would include field joint kits, flexible connectors, control and back-draft
dampers, bolt gaskets and two 40,000 cfm fiberglass exhaust fans.
ECS manufactured the ductwork using a state-of-the-art computerized filament winder. The fiber was impregnated with AOC’s Vipel
K022 corrosion-resistant vinyl ester resin. “The K022 resin was the
best choice for this project,” says ECS president Jeff Jones. “Some of
the gases in the air stream are corrosive — including hydrogen sulfide
and ammonia. There’s also sulfuric acid. Pipes built with this resin are
very resistant to what goes in them and they won’t easily corrode.”
To ease installation, ECS prefabricated and assembled duct subsections at its facility before shipping them and a field crew of five
MANHOLE COVERS
to handle field layup, to the construction site in Austin. “We work in
a controlled environment in the shop, but in the field you are open
to the elements,” adds Jones. “Some of the days we were in Austin
were cold and others were really hot. We had to adjust promotion
levels and add inhibitors to work with the resin long enough to do a
quality job under tough conditions.”
A key factor in the project’s success was that AOC’s Scott Lane,
product leader, and Eric Stuck, sales representative, offered technical assistance as ECS reformulated the resin to meet changing conditions in the field. Jones adds, “With the long runs and thick pipes,
we went through material much faster than normal, and AOC was
very good at meeting this fluctuation in demand.”
Composites replace cast iron on university campus
Ductile cast iron (cast iron
with added magnesium) has
been used for manhole covers
and frames since the mid-20th
Century due to its durability and
high compressive strength. Engineers who design underground
infrastructure
have
rarely
considered the use of alternative
materials. However, operators of
localized multibuilding heating
systems, such as those on college
campuses, have become increasingly aware of the dangers
posed by cast-iron manhole covers. Cast iron becomes very hot
when exposed to internal steam and external sunshine, and it also
conducts electricity — a concern when manhole covers are located
in walkways where students wear sandals or go barefoot in warm
weather. In addition, although cast iron stands up to heavy loads
and severe impacts, it is very heavy — the density of a cast-iron
manhole cover can be as high as 450 lb/ft3 (7,208 kg/m3). A small
32-inch/813-mm diameter cover can weigh as much as 250 lb/113.4
kg, which can lead to injuries to workers who have to move them.
Source | Fibrelite
Source | AOC
Corrosion protection for buried odor-control ductwork
These factors led the utilities department of a leading engineering university based in Cambridge, Mass., to replace traditional
manhole covers with composite versions manufactured by Fibrelite Composites (Skipton, North Yorkshire, U.K., and Pawcatuck,
Conn.). Many other universities in both the U.S. and Canada have
since followed suit, says the company.
Fibrelite uses multiaxial and woven glass reinforcements to
make a preform with a fiber architecture that maximizes bending
stiffness and strength-to-weight ratio. The preform is then infused
with polyester in a resin transfer molding process; for higher-temperature or highly corrosive applications, vinyl ester resin is used.
The thermal gradient properties of Fibrelite’s composite covers significantly reduce heat transfer from the steam vault below — the
surface temperature of the cover is typically only slightly higher
than the ambient temperature. Extensive testing has shown that
composite covers stay cool to the touch and support the same wheel
loads as 32-inch cast-iron manhole covers, yet they weigh nearly 70
percent less. Fibrelite emphasizes that its cover eliminates the possibility of electrical shock and resists corrosion caused by salts, oils,
water and steam and avoids theft of cast-iron covers, which have
value as scrap metal. As an added incentive, Fibrelite can permanently mold into the cover’s top surface any style of school logo or
other marking in single or multiple colors.
CT OCTOBER 2013
SEWER SYSTEM
41
Calendar
Nov. 6-7, 2013
Chemical Processing Symposium 2013
Galveston, Texas | www.acmanet.org
(click ‘events’)
High-Performance Composites for
Aircraft Interiors
Seattle, Wash. | www.compositesworld.com/
conferences
Oct. 2-4, 2013
JEC Americas 2013
Boston, Mass. | www.jeccomposites.com/
events/jec-americas-2013
Nov. 12-13, 2013 Composites Engineering Show 2013/
Automotive Engineering
Birmingham, U.K. |
www.compositesexhibition.com
Oct. 3-5, 2013
Turk Kompozit 2013
Istanbul, Turkey | http://turk-kompozit.org/en
Nov. 19-21, 2013 EWEA Offshore 2013
Frankfurt, Germany | www.ewea.org/events
Oct. 21-24, 2013 SAMPE Tech Conference
Wichita, Kan. | www.sample.org/events
Oct. 24-26, 2013 India Composites Show 2013
New Delhi, India |
www.indiacompositesshow.com
Oct. 28-29, 2013 The Composite Decking and Railing
Conference 2013
Baltimore, Md. | www.deckrailconference.com
Oct. 29-31, 2013 SAMPE China 2013
Shanghai, China | www.sampe.org.cn
DEC
Oct. 15-17, 2013 MATERIALICA 2013/eCarTec
Munich, Germany | www.materialica.com
Dec. 9-12, 2013
Carbon Fiber 2013
Knoxville/Oak Ridge, Tenn. |
www.compositesworld.com/conferences
MAR
Oct. 15-17, 2013 BIOFIBE 2013
Winnipeg, Manitoba, Canada | www.biofibe.com
NOV
Oct. 2-3, 2013
March 11-13,
2014
JEC Europe 2014
Paris, France | www.jeccomposites.com/
events/jec-europe-2014
APR
OCT
Calendar
April 13-17,
2014
2014 No-Dig Show
Orlando, Fla. | www.nodigshow.com
See more @ www.compositesworld.com/events
HAVE YOU HEARD THE BUZZ?
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with strength, integrity, and cost savings.
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• Architectural Structures
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42
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New Products
NEW
Products
Compression shuttle press
LMG (De Pere, Wis.) has introduced its largest-ever shuttle press. The 900ton system has a mold die capacity of 126 by 116 inches (3,200 by 2,946
mm). The total length of the press and shuttle system is 39 ft/11.9m. The
platen movement is facilitated by eight main rams and two jack cylinders.
Accurate platen parallelism is achieved with 45° adjustable gib guides on
four of its rectangular tie rods. The press was built to mold heavy parts as
large as 56 ft²/5.2m². Its shuttle system is designed to move the lower
from the mold. The system will soon be used to mold roof shells, with a 50
percent fiber volume, for the Roding Roadster Targa (Roding Automotive
GmbH, Roding, Germany). The polyurethane matrix resin will be prepared
by two RIM-Star Nano 4/4 metering machines, which are equipped for hightemperature process control with material temperatures up to 80°C/176°F.
The wear-optimized machine design reportedly will ensure permanent process stability with polyamide (PA), polyurethane (PUR) and epoxy resins. The
machine’s centerpiece is a new RTM mold carrier with a compact design and
a clamping force of 3,800 kN. The mold fixing area (1,300 by 1,300 mm,
or 51.2 by 51.2 inches) is said to be ideal for auto components as large as
1m²/10.8 ft². www.kraussmaffei.com
Pourable, addition-curing silicone
Hybrid structural adhesives
ADERIS's (Le Thillay, France) first line of hybrid structural adhesives, called
INES (INterlaced Elastomer NetworkS), are said to offer high structural
and sound-damping performance (suitable for automotive parts). The line
reportedly requires no primer on joint members and combines the performance of three adhesive bonding technologies: the resistance and
mechanical strength of epoxies; the elasticity provided by polyurethanes
(PUR); and the fast assembly rate enabled by methyl methacrylates (MMA).
ADERIS says this is the first time a structural adhesive combines elongation,
low modulus and high mechanical performance with high impact resistance and peel and shear strengths — 70 percent pure elasticity over an
elongation range in combination with high strength (250 kg/cm2 for shear
on steel and up to 100 kg/3.5 cm for peel) — and it does so in a range
of temperatures from -80°C to 140°C (-112°F to 284°F). The resulting
bond remains flexible, yet bonded parts may be handled soon after they
are joined. www.aderis-specialties.com
HP-RTM for automotive molding
KraussMaffei's (Munich, Germany) new RIM-Star high-pressure resin
transfer molding (HP-RTM) production cell is designed for series production
of carbon fiber-reinforced composite components that are paintable direct
Wacker Chemie AG (Munich, Germany) has developed ELASTOSIL VARIO,
a modular system for pourable silicone rubber compounds with two components that enter into an addition reaction at room temperature in the
presence of a platinum catalyst. The system permits adjustment of the
compound's reactivity and the hardness of the cured elastomer, enabling
compounders and silicone processors to tailor-make products. Suitable for
encapsulating and coating, for making technical molded parts and for moldmaking, the system consists of four modules: two base components and two
catalyst components. The former can be blended together in any ratio, and
so can the latter. From these modules, the processor mixes the two components of the RTV-2 silicone rubber compound in the quantities needed for
curing. The mixing ratios for the base and catalyst components can be varied
to match the silicone to the application. The hardness of the cured rubber is
determined by the ratio of the two base components in the mixture; Shore
A durometers range from 15 to 40. www.wacker.com
Fatigue analysis for wovens
Safe Technology Ltd. (Sheffield, U.K.) says the latest release of Safe’s
fe-safe/Composites (the add-on module to Safe’s fe-safe suite of fatigue
analysis software for finite element models) features a new tool for fatigue
analysis of woven fibers. Developed by Safe Technology and Firehole Composites (Laramie, Wyo., now part of Autodesk Inc., San Rafael, Calif.), the
module also extends current capabilities to new microstructures and loading
definitions, and it supports fatigue life predictions of plain-weave microstructures, using the same physics-based solution as that already applied
to unidirectional composites. Fatigue life predictions now can be completed
for multiaxial load states for which the material is not characterized. Further,
the applicable loading definitions have been expanded to allow for multiple
repeats and block loadings — useful for defining complex duty cycles (a
function used widely by wind turbine blade manufacturers). Finally, the effects of material healing at low stress levels have been included to accommodate infinite life scenarios that are often encountered in analyses with
low loads applied for long histories. www.safetechnology.com
CT OCTOBER 2013
mold half to the outboard station for material loading and to shuttle the
just-molded part to the opposite side for unloading. The press has a mold
load feature on the shuttle table that incorporates pins that come up
through the table to support the mold above the table as it is loaded via
forklift truck. After the forklift truck moves away, the pins lower the mold
into proper position. The press is controlled with an Allen Bradley PLC.
www.lmgpresses.com
43
Marketplace
Marketplace
MANUFACTURING EQUIPMENT & SUPPLIES |
Available in various temperature ranges
Used world wide by composite manufacturers
Distributed by:
AIRTECH INTERNATIONAL INC.
Tel: (714) s &AX
Website: http//:www.airtechintl.com
Manufactured by:
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PO Box 3855, City of Industry, CA 91744
ss Fax Website: http//:www.generalsealants.com
E-mail: [email protected]
Workholding
Solutions
for Metal,
Composites,
Ceramic and
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800-810-2482 • www.northfield.com
RECRUITMENT |
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Composites Industry Recruiting and Placement
COMPOSITES SOURCES
1IPOF
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COMPOSITESWORLD.COM
To Advertise in the
44
Composites Technology Marketplace
contact: Becky Helton
[email protected] 513.527.8800 x224
Showcase
SHOWCASE
Product & Literature
PERFORMANCE PTFE RELEASE AGENTS/
DRY LUBRICANTS FOR COMPOSITES
The Companies of North Coast
North Coast Tool & Mold Corp.
North Coast Composites, Inc.
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A&P Technology Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ITW Polymers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Airtech International . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
JRL Ventures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
AkzoNobel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Knoxville Oak Ridge Innovation Valley . . . . . . . . . . . . 21
ACMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
McClean Anderson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
AOC LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
North Coast Composites . . . . . . . . . . . . . . . . . . . . . . . . . 25
Ashby Cross Co. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Ross, Charles & Son Co. . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Baltek Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Saertex USA LLC . . . . . . . . . . . . . . . . . . . . . . . Back Cover
CCP Composites US . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
SPE Automotive Division . . . . . . . . . . . . . . . . . . . . . . . . 14
Chem-Trend Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Technical Fibre Products Ltd. . . . . . . . . . . . . . . . . . . . . . 33
Composites One LLC. . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
TenCate Advanced Composites USA . . . . . . . . . . . . . . 10
DIAB International . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Tricel Honeycomb Corp. . . . . . . . . . . . . . . . . . . . . . . . . . 42
Dieffenbacher GmbH. . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Wisconsin Oven Corp. . . . . . . . . . . . . Inside Back Cover
Elliott Co. of Indianapolis Inc. . . . . . . . . . . . . . . . . . . . . 11
Wyoming Test Fixtures Inc. . . . . . . . . . . . . . . . . . . . . . . 15
Henkel Corp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Zyvax Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inside Cover
CT OCTOBER 2013
INDEX OF ADVERTISERS
Interplastic Corp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
45
Engineering Insights
Composite
submarine
camels
WIN WITH
LONG-TERM
DURABILITY
The U.S. Navy wisely opts for more expensive submarine
moorings that maximize lifecycle cost-efficiency.
T
Design and engineering firm Whitman, Requardt & Assoc.
(WR&A, Baltimore, Md.) and composites manufacturer Composite
Advantage (CA, Dayton, Ohio) were tasked with developing a universal composite camel that would meet that challenge and accommodate any U.S. Navy sub type, anywhere in the world.
The Navy’s criteria for the new camel included not only the ability to absorb the energy generated by a berthing submarine, but
also the freeboard (how much of the camel would sit above the waterline), the list and trim angles, and the overall flotation stability
requirements. The Navy’s request for proposal (RFP) specified that
the level floating position of the camel must be maintained within
a 1-inch/25.4-mm tolerance side to side and front to back. Further,
the freeboard must be maintained within a 1-ft/0.3m tolerance.
The RFP also stipulated that the camels must meet performance
requirements in three load scenarios: berthing of a submarine,
mooring of a submarine and lowering and lifting the camel into and
out of the water. Berthing assumes a submarine velocity of 0.4 ft/sec
(0.12m/sec), which is approximately 200 ft-kip of energy. Mooring
loads — caused by waves, wind and other forces — are, by comparison, smaller than berthing forces. The load path for berthing and
mooring are horizontal, but the load path for lowering and lifting
the camel into and out of the
water is vertical; discrete lifting
points on the camel, therefore,
would be required and would
have to withstand an anticipated mass in excess of 45 metric
tonnes (100,000 lb).
“We were dealing with a
unique shape and the criteria
were somewhat at odds with
each other in that if we designed
to meet one requirement, issues
surfaced with the other criteria,”
says Matthew Lambros, structural engineer for WR&A. “This
was largely due to the fact that
a number of properties affecting
A finished camel awaits the berthing of a submarine.
the camel, such as volumes and
CO
OM
MP
PO
OS
S II T
TE
ES
SW
WO
OR
RL
LD
D .. C
CO
OM
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Source | Composite Advantage
his story begins with an unlikely premise: the U.S. Navy
needed to solve a problem, and it was willing to spend
more money up front on a solution if that solution promised
net savings in the long run. The problem? Poor durability of its
deep-draft submarine camels. These large and mostly submerged
metal or wood structures are attached to a mooring structure
and fitted with rubber bumpers to provide a buffer between the
Navy’s submarines and the waterfront where they are berthed. The
camel deflects or compresses with vessel movement and prevents
damage to the hull, diving planes, screws, fairings, special skin
treatments and other equipment by absorbing the sub’s energy —
which is considerable, given the 560-ft/171m length and 17,000
tons of water displaced by berthed vessels, including the Ohio
class submarine, the heaviest in the fleet.
Given the saltwater environment in which they work, metal and
wood camels require removal every two years for inspection and
repair, which can be substantial if corrosion has begun. The other
challenge the Navy faced was that it had 17 unique camel designs in
ports around the world. Each camel was designed to accommodate
a specific submarine type, which, in addition to the Ohio, includes
the Los Angeles, Virginia and Seawolf classes.
4
46
6
Rope ties
Wing wall
COMPOSITE ADVANTAGE’S
UNIVERSAL CAMEL FOR
U.S. NAVY SUBMARINE BERTHS
EXPLODED
VIEW
Deck
• Must withstand lifting mass in excess of 45 metric tonnes (100,000 lb)
• Must withstand berthing submarine velocity of 0.4 ft/sec
(0.12m/sec) or ~200 ft-kip of energy
FRONT VIEW
Upper box
25 ft/76m
11.5 ft/3.5m
Rubber fenders
Wing wall
Wing wall
Lower box
Wing wall
9 ft/2.7m
Front module
TOP VIEW
Front module w/ fenders
ENGINEERING CHALLENGE:
DESIGN SOLUTION:
Design a composite camel that meets the U.S. Navy’s requirements for
energy absorption, stability and long service life and can berth submarines of all classes.
A modular composite sandwich construction that allows camel ballast to be customized to meet trim and freeboard requirements while
absorbing the energy of berthing submarines.
densities, can vary and must be considered to establish precise flotation calculations.”
Working with CA, WR&A developed a design that comprises
five composite structures, or modules, that are assembled on site to
build the 25 ft by 9 ft by 11.5 ft (7.6m by 2.7m by 3.5m) camel. CA
president Scott Reeve says the two largest modules, the upper and
lower main boxes, are stacked (see photos). Two others, called wing
walls, are installed on each side of the stack, and a third module is
front mounted to provide the surface that faces the submarine. Attached to this front surface are the rubber fenders that contact the
submarine. On the backside of the camel, a series of ultrahigh molecular weight polyethylene rubbing strips provide a contact surface
where the camel meets the fixed dock structure.
The modules are made by assembling and bonding composite panels. Most panels have a sandwich construction, featuring
3.5-inch/89-mm thick TYCOR foam core (Milliken & Co., Spartanburg, S.C.) faced and edged with 0.3-inch/7.62-mm thick layers of uniaxial and triaxial glass fiber fabric from V2 Composites
(Auburn, Ala.). This structure is hand layed, vacuum bagged and
infused with Hetron 992 or Derakane 610 vinyl ester resin, supplied
by Ashland Performance Materials (Dublin, Ohio). The foam core
incorporates fiberglass shear webs, spaced at 1.5 inch/38.1 mm intervals. Where the panels are subjected to biaxial bending or significant shear forces, a bidirectional core is used. This consists of
unidirectional core that is cut into short lengths (perpendicular to
the shear webs) and wrapped in additional fiberglass fabric, thus
providing shear webs in both directions.
Reeve says some of the camel’s primary contact points — those
that see the most physical and mechanical stress — are designed for
impact resistance as 1.5-inch/38.1-mm thick solid laminates. Each
module and, later, the entire camel structure, is bonded together
with an adhesive provided by SCIGRIP (Durham, N.C.).
Structural analysis of the camel included a 3-D finite element
analysis (FEA) of the entire structure, using RISA-3D FEA modeling software developed by RISA Technologies (Foothill Ranch, Calif.). The model consisted primarily of a series of meshed plate
CT OCTOBER 2013
Illustration | Karl Reque
47
Source (all 3 photos) | Composite Advantage
Engineering Insights
The camel’s upper and lower boxes, each
about 9.1 ft tall by 25 ft wide by 11.5 ft deep
(2.8m by 7.6m by 3.5m), are stacked prior to
the addition of the wing walls, each 17.8 ft tall
by 5.5 ft wide by 11 ft deep (5.4m by 1.7m by
3.4m), visible at left and foreground.
With center boxes and wing walls assembled,
the fifth box, the front fender — measuring 18-ft
tall by 12-ft wide by 3.5-ft deep (5.5m by 3.7m
by 1.1m) — will be attached to the shadowed
area on the front of the center boxes.
elements; the material and section properties of the plate elements
were input manually to match the properties of the composite sandwich panels. Berthing, mooring and lifting (gravity) loads were applied to the model, and the resulting forces were used for panel and
connection design. The submarine berthing energy absorbed by the
marine fenders was converted to a force using charts and tables provided by marine fender manufacturers. The contact points from the
camel to the mooring structure were modeled using compressiononly lateral supports.
The panel properties were determined through an extensive testing program developed specifically for the camel design. For each
failure mechanism identified in the structural analysis, the panel
properties from the testing program were compared to the results of
the analysis to determine the factor of safety against failure. Reeve
says the calculated factors of safety were discussed with the owner,
engineer and fabricator to ensure there was a consensus regarding
their acceptability. Where possible, the safety factors also were compared to industry standards. For safety factors that were determined
to be insufficient, changes to the design or fabrication methods were
made as required.
COMPOSITESWORLD.COM
FABRICATING FOR FLOTATION
4
48
8
After the camel’s design was finalized and manufacturing began,
Reeve says another challenge presented itself: buoyancy management. Almost all of a camel rests below waterline, but the composite
camels are inherently too buoyant for the application. The goal, then,
was to put the camel’s center of gravity as far as possible below the
waterline to maintain rotational stability — easier said than done.
Reeve says calculating the center of buoyancy and center of
gravity included the tedious process of determining the relative position and density of each camel component, including panels, flotation foam, marine fenders and connection angles and hardware.
Increasing the ballast weight to achieve the required freeboard, for
example, would impact the angle of flotation. The final solution had
to achieve a balance among all the design criteria.
Ultimately, says Reeve, CA determined that ballast must be added to submerge the camel and keep it trim against the submarine.
An assembled submarine berth camel is
lowered into the water.
This is done in three ways. First, after the 70,000-lb/31,751-kg camel
is assembled, 35,000 lb/15,876 kg of concrete is poured into the center box. Second, a series of movable steel plates are installed over
the ballast; they are adjusted from side to side in the box after the
camel is floated for the first time to bring the entire structure trim.
Third, holes are drilled in the box sides to allow them to fill with
water. “The water helps keep the structure stabilized,” says Reeve. “It
doesn’t bob or move as much.”
CA’s first camel was assembled on site at Naval Submarine Base
New London (Groton, Conn.) in October 2010 and installed a
month later for a flotation test. Since then, the Navy has installed
two more camels, and CA is now manufacturing another for Naval
Station Norfolk (Norfolk, Va.). “Feedback from Navy facilities engineers and port operations is very favorable,” says CA vice president
Andy Loff. “Elimination of recurring maintenance is a major operational benefit, and multiple bases are now looking at the composite
camels for future use.”
Reeve says the Navy is installing about two composite camels per
year and is looking at other camel-like applications for the material,
despite the fact that the CA camels cost 40 to 50 percent more than
the old metal and wood versions. He lauds the unusual foresight:
“The Navy basically said, ‘I’d much rather pay a little more up front
than pay a lot more over a 10-year period.’” And with camels now
expected to last 25 years or longer, the savings will live on. Mission
accomplished. | CT |
Editor-in-Chief
Jeff Sloan, CT’s editor-in-chief, has been
engaged in plastics- and composites-industry
journalism for 20 years.
[email protected]
Read this article online | http://short.compositesworld.com/fU1KgKnR
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