S U B S T A N T IA T ION S OF A N A IR B OR N E S U B S T A N T IA

UNCLASSIFIED
Israel Aerospace Industries
Presented by Iddo Kressel
SUBSTANTIATIONS OF AN AIRBORNE
COMPOSITE RADOME MOUNTED ON AN
AIRCRAFT DOME
1
Summary
Full Scale Static Test
Elements Tests
Analysis
Substantiation Method
Radome Production
Radome Design
OUTLINE
UNCLASSIFIED
Radome trimming and inspection hangar
Substantiations of an Airborne Composite Radome
Mounted on an Aircraft Dome
2
UNCLASSIFIED
Reduction in labor & assembly
costs
Elimination of assembly
problems due to parts
manufacturing tolerances
Reduction in No. of parts
Optimal Electrical performance
Minimal weight – no splicing,
no rivets, etc…
Each Radome was designed as a
single, integral piece, thus
ensuring:
Design Concept
3
AEW Radome Design & Substantiation
• Honeycomb core
• Fiberglass skin
10 m
MAIN SPLICE
ANTENNA
2.0 m
UNCLASSIFIED
RADOME SHELL
ACCESS PANEL
3.2 m
SIDE SPLICE
Radome Design
CONNECTING
PLATE
4
AEW Radome Design & Substantiation
Interchangeability
UNCLASSIFIED
Lightning strike protection
Damage tolerance
Environmental conditions: -55oC to 70oC/wet
Minimal weight
Electrical requirements
Structural Design Criteria
5
AEW Radome Design & Substantiation
Honeycomb core
formed & NC machined
Automation in ply cutting,
lay up using laser
projector
Challenge in ensuring:
final geometry, uniform
temperature distribution
during curing process
Radome manufactured on
a steel lay-up tool
UNCLASSIFIED
Radome lay-up tool in the clean room
Radome Manufacturing
6
AEW Radome Production
UNCLASSIFIED
Software developed at IAI
for analysis of C-Scan data
Automated Inspection by Special “C” Scan
Ultrasonic Machine
AEW Radome Production
7
Building block approach:
Full-scale static test
for final proof
of structure
UNCLASSIFIED
Element tests for critical design details
Coupon tests for mechanical properties
Finite Element (FE) & detail stress analysis
Substantiation Method
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AEW Radome Design & Substantiation
Edge Specimen
UNCLASSIFIED
Leading Edge Test Specimen
Edge specimen (for tension and bending tests)
Leading edge typical structure
Element Tests
9
AEW Radome Design & Substantiation
UNCLASSIFIED
Loaded up to 220% ULT.
No failure, test stopped
Embedded defects
Environmental knock-Up
factor on loads
Two static tests
Edge specimens - Tension Test
Element Tests
Edge Specimen
Tension Test
10
AEW Radome Design & Substantiation
UNCLASSIFIED
Residual strength test up to 170% ULT
at RTD, No failure, test stopped
20 lifetimes
Embedded defects
Environmental aging
Two fatigue tests
Loaded up to 260% ULT.
Environmental knock-Up factor on load
Two static tests:
Edge Specimens - Bending Test
Element Tests
Edge Specimen
Bending Test
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AEW Radome Design & Substantiation
UNCLASSIFIED
Residual strength test up to 170% ULT at RTD
No failure, test stopped
20 lifetimes
Embedded defects
Environmental aging
Two fatigue tests
Loaded up to 440% ULT. No failure
Environmental knock-Up factor on load
Two static tests:
Leading Edge Specimen
Element Tests
Leading Edge Test
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AEW Radome Design & Substantiation
Radome mounted on a rigid rig
representing Dome interface
Test environmental condition: RTD
Test performed up to Ultimate load
Load enhancement factor to
account for variability &
environmental effects DR
Noise
C-Scan NDI
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Data Reductions and analysis
ULT load
Data Reductions and Analysis
NDI OK no new damages
Outer SurfaceNDI at
New
damages critical areas
UNCLASSIFIED
Outer SurfaceNDI at
New
damages critical areas
Limit load
Data Reductions and Analysis
Uniform pressure & 60% Limit load
NDI OK no new damages
DR
Radome test article identical to serial design
Full Scale Static Test
C-Scan NDI
AEW Radome Design & Substantiation
Leading Edge
Radome/Dome Splice
UNCLASSIFIED
Air Bag Zones
Internal pressure, on each cell, was applied by air-bags in
order to simulate the actual air load distribution
Average aerodynamic pressure for each cell was calculated
The Radome surface was divided into 52 cells
Full Scale Static Test Concept
14
AEW Radome Design & Substantiation
UNCLASSIFIED
Comparison Between Air-Bags Pressure
and Aerodynamic Loading
15
AEW Radome Design & Substantiation
241 strain &
14 displacement
channels.
UNCLASSIFIED
Left Hand Side & Right Hand Side
rig reactions measured
separately, to allow pressure
adjustment on each surface.
Each air-bag pressure is
controlled separately
Air-Bags Supporting Rig
Rod 5
Rod 6
Full Scale Static Test Concept
Rod 7
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Rod 8
Rod 3
Air-Bags
AEW Radome Design & Substantiation
Test Setup
UNCLASSIFIED
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AEW Radome Design & Substantiation
UNCLASSIFIED
Full Scale Static Test Set UP
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AEW Radome Design & Substantiation
Strain [µε]
-5000
-4000
-2000
-1000
0
1000
2000
4000
y [mm]
3000
UNCLASSIFIED
Outer ply, analysis
Outer ply, test results
-3000
Inner ply, test results
Inner ply, analysis
5000
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Leading Edge
Radial Strain Distribution at Radome Leading
Edge Ult. Test
AEW Radome Design & Substantiation
Strain [µε]
0
500
1000
1500
Inner ply, analysis
Inner ply, test
2500
UNCLASSIFIED
2000
3000
x [mm]
3500
Outer ply, analysis
Outer ply, test
C/L
Tangential Strain Distribution at Radome
C/L Ult. Test
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AEW Radome Design & Substantiation
UNCLASSIFIED
The two primary damage tolerance requirements were
addressed: damage growth characterization and residual
strength-capability
The substantiation method relied on analysis, supported by
testing at component and full-scale level.
Innovative design and manufacturing concepts allowed
construction of this Radome as a single integral part, thus
reducing cost and assembly problems.
A dome mounted composite Radome was designed and
substantiated for an early warning surveillance system.
Summary
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AEW Radome Design & Substantiation