Mech-Eng-26-1-2007 - Mechanical Engineering Scientific Journal

Transcription

Mech. Eng. Sci. J.
Vol.
No.
1
26
Ma{. in`. nau~. spis.
God.
pp.
Broj
Skopje
1‡38
str.
2007
Skopje
MA[INSKO IN@ENERSTVO ‡ NAU^NO SPISANIE
MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL
Izdava
Ma{inski fakultet, Univerzitet „Sv. Kiril i Metodij“, Skopje, R. Makedonija
Published by
Faculty of Mechanical Engineering, "SS. Cyril and Methodius" University, Skopje, R. Macedonia
Izleguva dva pati godi{no ‡ Published twice yearly
UREDUVA^KI ODBOR EDITORIAL BOARD
Odgovoren urednik Editor in Chief
Prof. d-r. Ivan Mickovski Prof. Ivan Mickovski, Ph.D.
Zamenik odgovoren urednik Co-editor in Chief
Von. prof. d-r Valentina Ge~evska Assoc. Prof. Valentina Gečevska, Ph.D.
Urednici
Doc. d-r Nikola Tuneski, sekretar
Prof. d-r Dobre Run~ev
Prof. D-r Slave Armenski
Prof. d-r Janko Jan~evski
Von. prof. d-r Jasmina âlovska
Asis. d-r Zoran Markov
Editors
Ass. Prof. Nikola Tuneski, Ph.D., secretary
Prof. Dobre Runčev, Ph.D.
Prof. Slave Armenski, Ph.D.
Prof. Janko Jančevski, Ph.D.
Assoc. Prof. Jasmina Čalovska, Ph.D.
Ass. Zoran Markov, Ph.D.
Tehni~ki urednik Technical editor managing
Blagoja Bogatinoski Blagoja Bogatinoski
Lektura
Ilinka Grubovi}
(angliski)
Georgi Georgievski
(makedonski)
Lectors
Ilinka Grubović
(English)
Georgi Georgievski
(Macedonian)
Korektor Proof-reader
Alena Georgievska Alena Georgievska
UDK: NUB „Kliment Ohridski“ ‡ Skopje UDC: "Sv. Kliment Ohridski" Library – Skopje
(Oqa Stojanova) (Olja Stojanova)
Tira`: 300 Copies: 300
Cena: 520 denari Price: 520 denars
Adresa Address
Ma{inski fakultet
(Ma{insko inènerstvo ‡ nau~no spisanie)
Odgovoren urednik
po{t. fah 464
MK-1001 Skopje, Republika Makedonija
Faculty of Mechanical Engineering
(Mechanical Engineering – Scientific Journal)
Editor in Chief
P.O.Box 464
MK-1001 Skopje, Republic of Macedonia
Mech. Eng. Sci. J. is indexed/abstracted in INIS (International Nuclear Information System)
www.mf.ukim.edu.mk
MA[INSKI FAKULTET, SKOPJE, REPUBLIKA MAKEDONIJA
FACULTY OF MECHANICAL ENGINEERING, SKOPJE, REPUBLIC OF MACEDONIA
Mech. Eng. Sci. J.
Vol.
No.
1
26
God.
pp.
Broj
Skopje
1‡38
str.
2007
Skopje
SODR@INA
377 ‡ Dame Korunoski, Ko~o An|u{ev, Hristijan Mickoski
Optimizaciona sinteza na ramni bregovi mehanizmi so oscilatorni ramni
vodeni ~lenovi so pomo{ na MATLAB........................................................................
1‡7
378 ‡ Marjan Gavriloski, Bekir Hamidi, Zoran Bogatinoski
Analiza na stabilnosta na tenkoyidni konstrukcii ..........................................
9‡15
379 ‡ Franc Čuš, Uroš Zuperl
Proizvodstven menaxment vo malite i sredni pretprijatija............................
17‡23
380 ‡ Zoran Ani{i}, Valentina Ge~evska
Konfiguratori na proizvod kako alat za podobruvawe na konkurentnosta
na mali i sredni kompanii ....................................................................................
25‡32
381 ‡ Marija Sejmenova-Gi~evska
Ulogata na Nacionalniot centar na INIS vo prezentacijata
na makedonskite nuklearni i nuklearno orientirani nauki ............................
33‡37
FACULTY OF MECHANICAL EGINEERING, SKOPJE, REPUBLIC OF MACEDONIA
MA[INSKI FAKULTET, SKOPJE, REPUBLIKA MAKEDONIJA
Mech. Eng. Sci. J.
Vol.
No.
1
26
God.
pp.
Broj
Skopje
1‡38
str.
2007
Skopje
CONTENTS
377 – Dame Korunoski, Kočo Angjušev, Hristijan Mickoski
Cam design optimization of planar cam mechanisms with oscillating flat-face
followers using MATLAB............................................................................................
1–7
378 – Marjan Gavriloski, Beqir Hamidi, Zoran Bogatinoski
Stability analysis for thin-walled constructions ................................................................ 9–15
379 – Franc Čuš, Uroš Zuperl
Produktionsmanagement in kleinen und mittleren Unternehmen ...............................
17–23
380 – Zoran Anišić, Valentina Gečevska
Product configurators as a tool for increasing competitiveness of small and medium
enterprises..................................................................................................................... 25–32
381 – Marija Sejmenova-Gichevska
The role of the National INIS Center in presenting Macedonian nuclear
and nuclear related sciences .......................................................................................... 33–37
Mechanical Engineering – Scientific Journal, Vol. 26, No. 1, pp. 1–7 (2007)
ISSN 1857–5293
UDK: 531.8 : 621.01] : 004.942
CODEN: MINSC5 – 377
Received: March 30, 2007
Accepted: June 20, 2007
Original scientific paper
CAM DESIGN OPTIMIZATION OF PLANAR CAM MECHANISMS
WITH OSCILLATING FLAT-FACE FOLLOWERS USING MATLAB
Dame Korunoski, Kočo Angjušev, Hristijan Mickoski
Faculty of Mechanical Engineering, "SS. Cyril and Methodius" University,
P.O Box 464, MK-1001 Skopje, Republic of Macedonia
[email protected] / [email protected] / [email protected]
A b s t r a c t: The problem of cam-profile determination and its optimization, as pertaining to cam mechanisms
with oscillating flat-face followers, is analyzed in this paper.
For this type of followers the aim is minimization of the
area of the cam profile by properly choosing the eccentricity
of the follower face and the minimum value of the follower
angle of rotation.
This paper shows MATLAB program based on “Symbolic Math Toolbox” that provides unconstrained cam-size
minimization and calculates an optimum design parameter β
and nondimensional eccentricity e for cusps avoidance. The
input program parameters are any function that describes a
follower-displacement program, rise of a follower and four
phases such as: lower dwell, rise phase, upper dwell, and return phase. So the output parameter is the optimum values of
the design parameter β and nondimensional eccentricity e
and synthesized cam-profile. The program provides a visual
graphical presentation of a synthesized cam-profile, its animation and calculates its geometric properties.
Key words: cam; cusp; eccentricity; MATLAB
1. INTRODUCTION
The process of systematically choosing the
mechanism parameters in order to produce a given
displacement program of the follower, while
minimizing the cam size and regarding all important constraints of mechanism variables, is called
cam design optimization, which is the subject of
analysis in this paper.
But, it is possible to choose values of the
mechanism parameters to produce theoretically the
prescribed motion of the follower which satisfies
the underlying kinematics constraints, but it is
structurally inadmissible or physically unfeasible.
In fact, the profile synthesis procedure can generate curves that do not close, so that it is an unfeasible design, or curves that, although closed, but
contain cusps. The cusps are inadmissible because
of the large contact stresses that they produce, and
hence should be eliminated early in the design
stage. In the case of oscillating flat face followers,
the conditions for cam size minimization and cusp
elimination are discussed and analyzed below in
this paper.
2. KINEMATICS RELATIONS
It will be assumed that the follower displacement program is given as a sum of a constant β, a
design parameter to be determined, and a positivesemidefinite function σ(ϕ), whose minimum value
is zero, and its maximum value being equal to the
amplitude of the follower oscillation, Δφ. Let us
consider Fig. 1, where OF and OC are lines attached to the fixed frame and to the cam respectively. Moreover, e is the follower offset-segment
PQ, a parameter to be determined, and ϕ, φ are the
angular displacements of the cam plate and the follower, respectively:
φ (ϕ ) = β + σ (ϕ ) , 0 < ϕ < 2π ,
(1a)
and hence,
φ ' (ϕ ) = σ ' (ϕ ) ,
φ '' (ϕ ) = σ '' (ϕ ) .
(1b)
2
D. Korunoski, K. Angjušev, H. Mickoski
Likewise, from the geometry of the quadrilateral OPQR and, upon equating the projection of
the segment OR with the sum of the projections of
the segments OP and PQ onto the normal ON of
Fig. 1, we can readily derive the relation
ρ sin(ϕ + φ + θ ) = l sin φ + e ,
(7)
and next, we rewrite eqs. (6 & 7) as
ρ cos θ cos μ − ρ sin θ sin μ = l
φ ' cos φ
,
1+ φ'
ρ cos θ sin μ + ρ sin θ cos μ = l sin φ + e ,
where
Fig. 1. Layout of an oscillating flat-face follower
cam mechanism
μ = ϕ +φ .
From the triangle OSR of Fig. 1, and upon
application of the sines law, we obtain
u
sin(γ −
π
2
=
)
ρ
sin(φ +
π
2
.
(2)
Now, last eqs. can be rewritten in a matrix
form,
Q ( μ ) p(ϕ ) = r (ϕ ) ,
⎡cos μ
Q(μ ) = ⎢
⎣ sin μ
But, from the same figure,
(3a)
π
2
) = cos(ϕ + φ + θ ) .
ered a point of the follower, s& F ,
φ ' (ϕ )
.
1 + φ ' (ϕ )
(5a)
(5b)
Now, eq. (4) can be rewritten as
ρ cos(ϕ + φ + θ ) = l
φ ' cos φ
.
1+ φ'
(9c)
η = l sin φ + e .
(9d)
Since the matrix Q is orthogonal, from eq. (8)
we obtain
p(ϕ ) = QT ( μ ) r (ϕ ) ,
(10)
i.e.
φ ' cos φ
cos μ + (l sin φ + e) sin μ ,
1+ φ'
(11)
φ ' cos φ
y = −l
sin μ + (l sin φ + e) cos μ .
1+ φ'
x=l
From which we can readily solve for u, i.e.,
uϕ& = l
(9b)
φ ' cos φ
,
1+φ'
ξ =l
(4)
According to the Aronhold-Kennedy Theorem, the point S is the instant center of the follower
with respect to the cam. As a consequence, the velocity of the point S regarded as a point of the cam,
s&C , equals that of the same points when considuϕ& = (l − u )φ& .
(9a)
(3b)
Upon substitution of eq. (3b) into eq. (2), we
obtain
u cos φ = ρ cos(ϕ + φ + θ ) .
− sin μ ⎤
,
cos μ ⎥⎦
⎡ x(ϕ ) ⎤
⎡ξ (ϕ )⎤
p(ϕ ) = ⎢
, r (ϕ ) = ⎢
⎥
⎥,
⎣ y (ϕ )⎦
⎣η (ϕ )⎦
And hence,
sin(γ −
(8)
where
)
γ = π − (ϕ + φ + θ ) .
(7a)
(6)
While eqs. (11) allow the calculation of the
Cartesian coordinates of actual points of the cam
profile, it will prove convenient to introduce nondimensional variables, as shown bellow,
e
x
y
ξ
η
e= , x= , y= , ξ = , η =
l
l
l
l
l
Mech. Eng. Sci. J., 26 (1), 1–7 (2007)
3
Cam design optimization of planar cam mechanisms with oscillating flat-face followers using MATLAB
and hence, eqs. (11) can be rewritten in a matrix
form,
where
s1 = sin σ , c1 = cos σ ,
s2 = sin 2σ , c2 = cos 2σ ,
φ ' cos φ
x=
cos μ + (sin φ + e ) sin μ ,
1+ φ'
(11b)
φ ' cos φ
y=−
sin μ + (sin φ + e ) cos μ .
1+ φ'
⎡ x (ϕ ) ⎤
p(ϕ ) = ⎢
⎥ , r (ϕ ) =
⎣ y (ϕ )⎦
⎡ξ (ϕ ) ⎤
⎢
⎥.
⎣η (ϕ )⎦
(11c)
The shape of the profile is totally determined
by e and the motion program, the actual size of
the cam being determined by the scaling parameter l.
However, from eq. (1a), φ(ϕ) contains the parameter β, which must also be found. To summarize, there are two parameters, e and β, to minimize the size of the non-dimensional cam.
φ '2
,
1+ φ '
(17)
φ"
,
(1 + φ ' ) 2
(18)
A1 =
Vectors p(ϕ) and r(ϕ), introduced in eq. (9b),
are now redefined as their non-dimensional counterparts, namely
A2 =
(16)
A3 = 1 + φ ' .
(19)
Once β has been found, the eccentricity e
can be computed by the expression,
2π e + U 2 sin β + U1 cos β = 0 .
(20)
4. CURVATURE CONSTRAINTS
Regarding to [1], the curvature is given by
expression
3. UNCONSTRAINED CAM-SIZE
MINIMIZATION
k=
p'T (ϕ ) E p" (ϕ )
p' (ϕ )
3
.
(21)
According to the [1], [2], the problem has
been reduced to finding the roots of an equation,
Differentiation of both sides of eq. (8) with
respect to ϕ yields
t 4 − Ct 3 − 6t 2 + Ct + 1 = 0 ,
p' (ϕ ) = Q T ( μ )[r' (ϕ ) − μ ' (ϕ ) E r (ϕ )] ,
(12)
where
t = tan
β
2
,
2B
C= 3,
B1
B1 = 2πU 4 − U1U 2 ,
B3 = 4πU 3 − U 22
where
⎡0 − 1⎤
E=⎢
⎥,
⎣1 0 ⎦
(13)
(14)
+ U12
(15)
and differentiation of both sides of eq. (22) with
respect to ϕ , we obtain
p" (ϕ ) = QT ( μ )[r" (ϕ ) − μ" (ϕ ) E r (ϕ ) −
and
2π
2π
2π
0
0
0
2π
2π
2π
0
0
0
2π
2π
2π
0
0
0
U1 = ∫ A1s1dϕ − ∫ A2c1dϕ − 2 ∫ A3 s1dϕ ,
2 μ' (ϕ ) E r' (ϕ ) − μ' 2 (ϕ )r (ϕ )]
μ ' (ϕ ) = 1 + σ ' (ϕ )
μ " (ϕ ) = φ " (ϕ ) = σ " (ϕ ).
From eq. (11c), r and its derivatives are
U 3 = ∫ A1c2 dϕ − ∫ A2 s2 dϕ − ∫ A3c2 dϕ
2π
2π
2π
0
0
0
Ma{. in`. nau~. spis., 26 (1), 1‡7 (2007)
(23)
where
U 2 = ∫ A1c1dϕ + ∫ A2 s1dϕ − 2 ∫ A3c1dϕ ,
U 4 = ∫ A1s2 dϕ − ∫ A2c2 dϕ − ∫ A3 s2 dϕ ,
(22)
⎡ξ ⎤
⎡ξ '⎤
⎣η ⎦
⎣η '⎦
⎡ξ "⎤
⎥
⎣η "⎦
r (ϕ ) = ⎢ ⎥ , r' = ⎢ ⎥ , r" = ⎢
Now,
(24)
4
From eq. (29b), it is apparent that k becomes
negative if 1 + φ ' < 0 . However, changes in the curvature sign are not physically possible for this type
of cams and hence we must constrain k to be positive, i.e.,
⎡ξ '+ μ 'η ⎤
r' − μ ' E r = ⎢
⎥,
⎣η '− μ ' ξ ⎦
but from eqs.(7a, 9c & d) it yields
η '− μ ' ξ = 0 ,
1+ φ' > 0 .
and hence, the foregoing expression reduces to
Moreover, k becomes unbounded if F (ϕ )
vanishes. Geometrically, this means that the cam
profile has a cusp, which is undesirable bacause of
the large contact stresses that it produces. Thus, we
will have to enforce the condition that F (ϕ ) does
not have a change of sign.
⎡ξ '+ μ 'η ⎤
r' − μ ' E r = ⎢
⎥,
⎣ 0 ⎦
thus
⎡ξ '+ μ 'η ⎤
p' (ϕ ) = QT ( μ ) ⎢
⎥,
⎣ 0 ⎦
(25a)
5. CONCLUSION
and
⎡ξ "+ μ "η + μ 'η '⎤
p" (ϕ ) = QT ( μ ) ⎢
⎥.
⎣ − μ ' ξ '+ μ 'η ⎦
[
]
(25b)
Substitution of eqs. (25a & b) into eq. (21)
and after reducing, yields
k=
μ'
.
ξ '+ μ 'η
(26)
Based on [1], [2] and [4], we have made a
MATLAB program that provides unconstrained
cam-size minimization and calculates an optimum
design parameter β and non-dimensional eccentricity e for cusps avoidance. The program also provides animation of an optimized and synthesized
cam-profile and calculation of its geometric properties as well as centroid coordinates, cam area and
principal moments of inertia. For one example it is
presented in the appendix shown bellow.
From the definition of μ and ξ , i.e.,
φ ' cos φ
μ =ϕ +φ , ξ =
,
1+ φ'
REFERENCES
(27)
their derivatives are readily computed
μ' = 1+ φ' ,
ξ '= −
φ '2 (1 + φ ' ) sin φ + φ " cos φ
.
(1 + φ ' ) 2
(28a)
(28b)
Upon substitution of the above equations into
eq. (26) and after simplification, we obtain
(1 + φ ' )3
k=
,
F (ϕ )
(29a)
F (ϕ ) = φ " cos φ + (1 + φ ' ) ⋅
⋅ [(1 + 2φ ' ) sin φ + e (1 + φ ' ) 2 ].
(29b)
where
[1] J. Angeles, C. S. Lopez-Cajun: Optimization of cam
mechanisms, Kluwer Academic Publishers, 1991.
[2] J. Angeles, C. S. Lopez-Cajun: Optimal Synthesis of Cam
Mechanisms with Oscillating Flat-Face Followers.
Mechanism and Machine Theory, Vol. 23, No. 1, pp. 1–6
(1988).
[3] A. Jeffrey: Mathematics for Engineers and Scientists,
Van Nostrand-Reinhold, London, 1989.
[4] The MathWorks, Inc.: Matlab, User manual.
APPENDIX
a) Figure 2: MATLAB program for cam design optimization.
b) Figure 3: Optimization variables.
c) Figure 4: Determination of the cam profile.
d) Figure 5: Determination of the geometric
properties of cam.
e) Figure 6: Principal axes of inertia.
Mech. Eng. Sci. J., 26 (1), 1–7 (2007)
Fig. 2. MATLAB program for cam design optimization
Fig. 3. Optimization variables
Ma{. in`. nau~. spis., 26 (1), 1‡7 (2007)
5
6
Fig. 4. Determinaton of the cam profile
Fig. 5. Determinaton of the geometric properties of cam
Mech. Eng. Sci. J., 26 (1), 1–7 (2007)
7
Fig. 6. Principal axes of inertia ( 1 & 2 )
Rezime
OPTIMIZACIONA SINTEZA NA RAMNI BREGOVI MEHANIZMI SO OSCILATORNI
RAMNI VODENI ^LENOVI SO POMO[ NA MATLAB
Dame Korunoski, Ko~o An|u{ev, Hristijan Mickoski
Ma{inski fakultet, Univerzitet „Sv. Kiril i Metodij“
p. fah 464, MK-1001 Skopje, Republika Makedonija
[email protected] // [email protected] // [email protected]
Klu~ni zborovi: breg; vrv; ekscentricitet; matlab (MATLAB)
Predmet na analiza vo ovoj trud e optimizaciona sinteza na ramni bregovi mehanizmi so oscilatorni ramni vodeni ~lenovi. Kaj ovie mehanizmi osnovno e da se minimizira povr{inata zatvorena so
profilot na bregot, so adekvaten izbor na ekscentricitetot na vodeniot ~len i so minimalna vrednost na
agolot na rotacija na vodeniot ~len. Vo trudot e napravena MATLAB-programa, bazirana na “Symbolic
Math Toolbox”, koj presmetuva minimalni dimenzii na
bregot, kako i optimalna vrednost na dizajn-parametarot β i bezdimenzionalniot ekscentricitet e , od
Ma{. in`. nau~. spis., 26 (1), 1‡7 (2007)
aspekt na nepostoewe na singulariteti na profilot
na bregot, t.e. to~ki vo koi bi se pojavile golemi
kontaktni napregawa. Vleznite parametri se: koja i
da bilo funkcija koja go opi{uva zakonot na dvièwe na vodeniot ~len, odot na vodeniot ~len i ~etiri
fazi: fazata na dolno miruvawe, fazata na podigawe,
fazata na gorno miruvawe i fazata na pribliùvawe. Izleznite parametri se dizajn-parametarot β i
bezdimenzionalniot ekscentricitet e , profilot na
bregot, geometriskite karakteristiki na bregot, a
mo`na e i animacija na rotacijata na bregot.
ISSN 1857–5293
UDK: 539.3 : 624.014.7
Received: October 15, 2007
Accepted: October 30, 2007
STABILITY ANALYSIS FOR THIN-WALLED CONSTRUCTIONS
Marjan Gavriloski1, Beqir Hamidi2, Zoran Bogatinoski1
1
2
Faculty of Mechanical Engineering, University of Priština
[email protected]
A b s t r a c t: Stability of light constructions problem
for a general scalar discrete stochastic system is considered in
this paper. Some elements of the structure, in practice, are
exposed to the axial dynamic pressure forces – periodical.
These loads, in some conditions, can cause the loss of elastic
or dynamic stability (resonance), which depends on the load
character, cross sectional geometry and the beam length. In
this paper, the light constructions with open cross section with
a single symmetry axis, the conditions when the loss of elastic
and dynamic stability can be caused by simple resonance, as
one of parameter have been analyzed.
Key words: elastic and dynamic stability; parameter resonance; excitation frequency light constructions;
critical bucking force
∂2w
K=
∂ x2
⎡ ⎛ ∂ ⎞2 ⎤
⎢1 + ⎜⎜ w ⎟⎟ ⎥
⎢ ⎝ ∂x ⎠ ⎥
⎣
⎦
2/3
As given in [1, 2, 3, 4] the deflection line equations,
for the beam flexible in one plane, can be expressed (in
accordance with the theory of the first order) as:
EI
∂4w
∂ x4
= q (x ) ,
∂ 2w
∂ x2
(2)
The additional working force can be caused
by the local curve (Fig. 1-b):
∂ 2w
1
q A ( x)dx = Fdϕ = F dx = FKdx = − F 2 dx →
r
∂x
q A ( x) = − F
1. BASIC DIFFERENTIAL EQUATION
≈−
∂2w
∂x 2
(3)
If this working force is added in equations
(1), the General differential equations of the bending theory of the second order will be determined
(in conditions, when the beam bending and buckling are in the single plane ) as:
(1)
where:
EI – the flexural stiffness,
w(x) – the displacement measured from the
truss axes,
q(x) – continual load (Fig. 1).
When the beam is exposed to the eccentric
axial pressure force F, the buckling problem in
accordance with the theory of the second order appears [4]. The angle of the segment dx is indicated
as dϕ and dx = rdϕ, where r is the local radius of
the curve, and is reciprocal to r = 1/K:
Fig. 1.
10
M. Gavriloski, B. Hamidi, Z. Bogatinoski
EI
∂4w
∂x 4
= q ( x) + q A ( x) = q ( x) − F
EI
∂4w
∂x 4
+F
∂2w
∂x 2
= q ( x)
∂2w
∂x 2
→
(4)
Equations for the three axial bending and torsion of the thin-walled beams with open profile
and single symmetry axis of the cross section, exposed to eccentric pressure loads, can be obtained
analogously. The particle of the beam with dx
length, exposed to the external loads qz, qy and mt,
is shown on Fig. 2.
EIy, EIz – the flexural stiffness referred to y,
i.e. z axis,
EIw – area rigidity, and
GIz – the torsional stiffness.
The beam is exposed to the eccentric pressure
force F, in the plane of symmetry, as shown in Fig.
2. The fiber stress in the node y, z, in the cross section, can be expressed as:
σ=
F M
+
z,
A Iy
(8)
where M = Fez is the flexural momentum caused
by the eccentric force F. In three axial bending and
buckling, the lateral displacements – buckling v(x)
and torsional ϕ(x), can be caused on distance x
(Fig. 2-c). The fiber which goes through the node
y, z, becomes the three axial curves. The node displacements, in the directions of y and z axes, are:
[ v − ( z − a z )ϕ ], i.e. [ w + yϕ ] .
(9)
In accordance with equations (3), the working
forces caused by the local stress effect σdA, in the
direction of y and z axes, are:
− σdA
∂2
[v − ( z − az )ϕ ] ,
∂x 2
− σdA
Fig. 2.
The beam supported by two fork – supports,
exposed to the axial pressure force F, eccentric to
the center of mass with ez distance of it, is shown
on Fig. 2-b. The value az is the distance between
the shearing center from the center of the mass.
The deformations in direction of coordinate axes y,
z are v, w, respectively, and the torsion angle about
x axis is ϕ.
The basic equations, according to the theory
of the first order, are [6, 1]:
EI y
EI z
EI w
where:
∂ 4ϕ
∂ 4w
∂x 4
∂ 4v
∂x 4
= qz ,
(5)
∂ 2ϕ
GI
= mt ,
−
∂x 2
∂x 4
(6)
(7)
(10)
Integrating along the cross section area A, the
resulting local effect, as well as the torsion momentum about the torsion center „A”, can be determined:
q y , A = ∫ −σ
A
∂2
[v − ( z − az )ϕ ] dA ,
∂x 2
(11)
∂2
[w + yϕ ] dA ,
∂x 2
(12)
q z , A = ∫A −σ
mt , A = − ∫A −σ
∂2
[v − ( z − az )ϕ ] ⋅ (z − az ) dA +
∂x 2
+ ∫ −σ
= qy ,
∂2
[ w + yϕ ] .
∂x 2
A
∂2
∂x 2
[w + yϕ ]⋅ ydA .
(13)
Integrating the equations (11), (12) and (13),
and taking the equation (8) into consideration, the
following can be obtained:
q y ,A = −F
∂ 2v
∂x 2
− (ez − a z )F
∂ 2ϕ
∂x 2
,
(14)
Mech. Eng. Sci. J., 26 (1), 9–15 (2007)
11
Stability analysis for thin-walled constructions
qz ,A = −F
mt , A = −(a z − ez )F
∂ 2v
∂x 2
∂2w
∂x
2
,
(15)
(
)
− r 2 + 2 β z ez F
∂ 2ϕ
∂x 2
, (16)
where:
r 2 = i 2p + a z2 ,
βz =
(
(17)
)
1
2
2
∫ z y + z dA − a z ,
2I y A
I y + Iz
i 2p =
A
∫ zdA = 0,
∫ ydA = 0,
∫ yzdA = 0.
EI y
EI z
∂ 4w
∂x 4
+F
∂ 2w
∂x 2
= 0,
(20)
∂ 4v
∂ 2ϕ
∂ 2v
(
)
a
e
F
= 0 , (21)
F
+
+
+
z
z
∂x 2
∂x 2
∂x 4
∂ 4ϕ
+
∂x 2
∂x 4
∂ 2ϕ
+ r 2 + 2β z ez F − GI t
= 0.
∂x 2
(az − ez )F ∂
[(
2
v
)
+ EI w
]
(22)
Equations (21) and (22) are mutually dependant on v and ϕ . Thus, they make the simultaneous
system of the differential equations. The system of
equations (20), (21) and (22) is a specific case
(when ay = ey = 0 is adopted) derived from the system of differential equations for the general load
case, according to Wlassow [6]. If the inertial parts
are introduced in the equations (20), (21) and (22),
the equations for the oscillations of the thin-walled
beam with an open profile and one axis of symmetry in the cross section, exposed to the eccentric pressure periodical forces F(t) = F0 + Ft cosθ t in the
Ma{. in`. nau~. spis., 26 (1), 9‡15 (2007)
∂ 2ϕ
−
ma
,
z
∂t 2
∂t 2
m A,in = − mr 2
∂ 2w
∂t 2
(23)
,
(24)
∂ 2ϕ
∂ 2v
−
ma
z 2.
∂t
∂t 2
(25)
If the equations are substituted in (20), (21)
and (22), the system of differential equations
which describes the oscillations of the beam, is
determined as:
A
When the local effects (14), (15) and (16) are
added in eqs. (5), (6) and (7), the system of the differential equations, which define the static stability
of the thin-walled beam with the single axis of
symmetry exposed to the constant axial pressure
force in the plane of symmetry, will be obtained,
as:
∂ 2v
q z ,in = − m
(19)
,
A
q y ,in = − m
(18)
ip – the cross sectional polar radius of inertia.
Solving the integrals (11), (12) and (13), the
following is adopted (for the general central axis):
A
plane of symmetry, can be obtained. The components which describe the rotation of the cross section about its main axes and its deplanation too,
can be neglected. The inertial forces projections on
directions y and z axes, as well as the inertial momentum about the shearing center (reduced to the
length of the beam) can be expressed as [7]:
EI y
EI z
∂ 4w
∂ 2w
∂ 2w
= 0,
+
F
m
+
∂x 4
∂x 2
∂t 2
(26)
∂ 4v
∂ 2v
∂ 2ϕ
(
)
+
F
+
a
−
e
F
+
z
z
∂x 2
∂x 2
∂x 4
+m
∂ 2v
∂ 2ϕ
+
ma
= 0,
z
∂t 2
∂t 2
∂ 4ϕ
+ EI w 4 +
∂x
∂x 2
∂ 2ϕ
+
+ r 2 + 2 β z ez F − GI t
∂x 2
∂ 2v
∂ 2ϕ
+ maz 2 + mr 2 2 = 0.
∂t
∂t
(az − ez )F ∂
2
(27)
v
[(
]
)
(28)
The system of equations given in (26), (27)
and (28) is the basis for the researches of the dynamic stability of the beam. The boundary conditions, for the beam supported on both ends, are:
v(0) = w(0) = ϕ (0) =
v(l ) = w(l ) = ϕ (l ) =
∂ 2v(0)
∂x 2
∂ 2 v(l )
∂x 2
=
=
∂ 2 w(0)
∂x 2
∂ 2 w(l )
∂x 2
=
=
∂ 2ϕ (0)
∂x 2
∂ 2ϕ (l )
∂x 2
=0,
=0.
(29)
They can be developed as trigonometric progressions as:
12
kπx
,
l
∞
v( x, t ) = ∑ Vk (t ) sin
k =1
⎡ EI z x 4
[Rk ] = ⎢
⎢⎣
kπx
,
l
∞
w( x, t ) = ∑ Wk (t ) sin
k =1
∞
ϕ ( x, t ) = ∑ Φ k (t ) sin
k =1
(30)
where Vk (t ), Wk (t ), Φ k (t ) are some time dependant functions. When progressions (30) are
seated in (26), (27) and (28), the system of the homogenous different equations can be determined as
[6, 7]:
d 2Wk
m
dt 2
+ EI y xk4Wk − xk2 F (t )Wk = 0 ,
d 2Vk
d 2φk
+
ma
+ EI z xk4Vk −
z
2
2
dt
dt
− xk2 F (t )[Vk + (a z − ez ) φk ] = 0,
m
d 2Vk
(
(
⎣
) ⎦
(32)
⎥
+ GIt xk2 ⎥⎦
,
a z − ez ⎤
.
+ 2β z ez ⎥⎦
r2
From the eq. (34), the following can be obtained:
1) an equation for determination of the critical
forces (the static stability of the beam):
det [Rk ] − xk2 F [S ] = 0,
(35)
2) an equation for determination of the eigenvalues, the case of unloaded beam:
(31)
det [Rk ] − mw2 [D ] = 0,
(36)
3) an equation for determination of the eigenvalues, for the beam exposed to the constant axial
force:
det [Rk ] − xk2 F [S ] − mΩ 2 [D ] = 0 ,
)
d 2φk
ma z
+ mr 2
+ EI w xk4 + GI t xk2 φk −
dt 2
dt 2
− xk2 F (t ) (a z − ez )Vk + r 2 + 2β z ez φk = 0
(k = 1, 2..., ∞ ),
0
⎤
o
EI w xk4
⎡ 1
⎧Vk ⎫
⎬, [S ] = ⎢
⎩φk ⎭
⎣ a z − ez
{δ k } = ⎨
kπx
,
l
k
(33)
where xk = kπ /l.
Equations (31), (32) and (33) present the special case of the system of differential equations
derived by Wlassow (about eigenvalues [6]) and
GolÝdenblag (about dynamic stability [7]). Equation (31) is independent, since the equations (32)
and (33) are mutually coupled in term of Vk and φk,
i.e. they form the endless series of the simultaneous system of homogenous differential equations.
Thus they are of specific interest, while the equation (28) is disregarded from further consideration.
(37)
4) an equation for determination of the first,
the third etc., area of the dynamic instability, when
the beam is exposed to the periodical force:
F(t) = F0 + Ftcos θt developed as Fourier’s series [6]:
[Rk ] − ⎛⎜ F0 ± 1 Ft⎞⎟ [S]
1
− xk2 Ft [S]
2
2 ⎠
1 2
1
− mθ [D] − xk2 Ft[S]
4
2
[Rk ] − xk2F0[S] −
0
9
1
− mθ 2 [D] − xk2 Ft [S]
4
2
⎝
o
1
− xk2 Ft [S] = 0
2
[Rk ] − xk2F0 [S]
25
− mθ 2 [D]
4
(38)
and the analogue equation for determination of the
even areas of the dynamic instability.
2. BASIC EQUATIONS IN MATRIC FORM
Endless series of the simultaneous equations
system (32), (33) can be expressed in matrix form, as:
d2
m[D ] 2 {δ k } +
dt
where:
([
[S ]){δ k } = {0},
]
Rk − xk2 F (t )
[D] = ⎡⎢
1
⎣a z
az ⎤
,
r 2 ⎥⎦
(34)
3. ELASTIC STABILITY OF THE BEAM
The static stability of the thin-walled beam
with the open cross section and single axis of
symmetry, exposed to eccentric, mutually equal,
axis loads in the plane of symmetry can be disturbed if the force amounts the critical value F.
From the equation (35) (when k = 1 – main mode
shape), the formulation for the critical buckling
force F, can be obtained as:
Mech. Eng. Sci. J., 26 (1), 9–15 (2007)
13
F=
π 2 EI z
⋅
l2
2c 2
⎡
r 2 + 2 β z ez − (a z − ez )2 ⎤⎥
c 2 + r 2 + 2 β z ez ⎢1 ± 4c 2
2
⎢
⎥
c 2 + r 2 + 2 β z ez
⎣
⎦
(
)
(
)
(39)
where c is "the cross sectional revolving radius".
c 2 + r 2 + 2β z ez
2c 2
l2
EI z
,
m
2
⎛
2
⎜1 ± 1 − 4c 2 r + 2 β z e z − (a z − e z )
2
⎜
c 2 + r 2 + 2β z ez
⎝
(
)
⎞
⎟
⎟
⎠
Analogous, the formulation for the ideal slenderness (for the referent truss) can be determined as:
l
iz
⎛
c 2 + r 2 + 2 β z ez ⎜
r 2 + 2β z ez − (az − ez )2
1 ± 1 − 4c 2
⎜
2
2
⎜
2c
c 2 + r 2 + 2β z ez
⎝
(
)
⎞
⎟
⎟⎟ .
⎠
(42)
If the applied load is not eccentric (ez = 0), the
formulations (39), (41) and (42) will be slightly
simplified.The critical buckling force will be as:
F* =
π 2 EI z
,
β 2l 2
1
2
2
r2
1− γ ±
(46)
2
ω = ωy
, (47)
⎛ a2 ⎞
1 + γ ± (1 + γ )2 − 4γ ⎜1 − 2z ⎟
⎜ r ⎟
⎝
⎠
and the other two as:
1+ γ ±
ω = ωy
⎛
2⎞
⎝
r ⎠
(1 + γ )2 − 4γ ⎜⎜1 − a2z ⎟⎟
⎛ a2 ⎞
2γ ⎜1 − 2z ⎟
⎜ r ⎟
⎠
⎝
. (48)
Very often, in practice, it is the case that
γ << 1. Therefore, it can be very useful to determine the boundary values, i.e. values when γ → 0.
From the equation (48) it appears that (the actual
sign „±” appears in the index):
γ → 0 ⇒ ω+ → ωy ∧ ω– → ∞
(49)
and from the equation (49):
⎛ r2 ⎞
a 2
β=
1 − 2 ± ⎜1 − 2 ⎟ + 4 z2 ,
⎜ c ⎟
2
c
c
⎝
⎠
β=
lr
The first two roots of the equation (46) are
defined as:
(43)
where β will be the length coefficient determined as:
1
⎞
π2
l ⎛
⎜ EI ω
+ GI t ⎟⎟ . (45)
2
⎜
m⎝
l
⎠
π2
(ω 2y − ω 2 )(ωϕ2 − ω 2 )− ar 2z ω 4 = 0.
(41)
λzi =
ωϕ =
From the equation (36), the following will be
obtained:
(40)
When the equation (39), for the critical force,
is equalized with the equations for the buckling
force of the referent truss, with its buckling length
sk, (i.e. the referent truss length), sk i.e. the length
coefficient β will be determined as:
β=
π2
2
Iω l 2GIt
+
.
I z π 2 EI z
C=
ωy =
2
(1 − γ )2 + 4 az2
c
,
γ=
r2
c2
, (44)
γ → 0 ⇒ ω+ → ω y
Thus, the eigenvalues of the thin-walled beam
exposed to the constant axial force F0, can be determined from the equation (37). If the following
relations are adopted as:
μ=
where γ is non-dimensional geometry characteristic of the cross section.
Fϕ =
4. PARAMETER STABILITY OF THE BEAM
The unloaded beam eigenvalues can be determined from the equation (36). Let us consider
just the basic mode shape, i.e. when k = 1 is replaced in equations. If the partial frequencies (the
buckling and the torsion) are identified as:
Ma{. in`. nau~. spis., 26 (1), 9‡15 (2007)
c
r
= ω p ∧ ω − → 0. (50)
ip
ip
p2 =
F0
, Fy = xk2 EI z ,
Fy
1
r2
(EIω xk2 + GIt xk2 ) ,
r 2 EI z xk2
Fy ω y2
Ω2
r2
,
=
=
=
=
,
γ
Fϕ ωϕ2 EIω x 2 + GI t c 2
ω y2
k
from the equation (37) will be obtained:
14
(1 − μ − p 2 )⎡⎢1 − γμ ⎛⎜⎝1 + 2βrz2ez ⎞⎟⎠ − γ p2 ⎤⎥ −
⎣
⎦
2
γ
− 2 [μ (a z − ez ) + a z p 2 ] = 0.
r
(51)
The equation (52) is of the fourth order, so it
has four roots. The first two are determined as:
Ω 2 = ω y2 ⋅
2A
B ± B 2 − 4 AC
,
1 − (μ ± v ) − n 2
a − ez
− γ (μ ± v ) z
− az n2
2
r
− (μ ± v )(a z − e z ) − a z n 2
2β z e z ⎞ − γn 2 = 0
⎛
1 − γ (μ ± v )⎜1 +
⎟
r2 ⎠
⎝
where:
μ=
(52)
F0
F
Ω2
, v = t , n2 = 2 ,
Fy
2 Fy
ωy
Fy = x k2 EI z , Fϕ =
while the other two are:
B ± B 2 − 4 AC
Ω 2 = ω y2 ⋅
,
2C
(53)
where:
γ =
Fy
Fϕ
=
ω y2
ωϕ2
=
1
r2
(EI ω x
2
k
)
+ GI t x k2 ,
r 2 EI z x k2
EI w x k2 + GI t
=
r2
c2
(57)
.
The roots of the equation (58) are expressed as:
⎧
⎛ 2β e ⎞
A = 1 − μ ⎨1 + γ ⎜1 + z2 z ⎟ −
r ⎠
⎝
⎩
⎛ 2 β e − (a − e )2 ⎞⎫⎪
− γμ ⎜1 + z z 2 z z ⎟⎬
⎟⎪
⎜
r
⎠⎭
⎝
θ∗2 = 4ω 2y ⋅
θ∗2 = 4ω 2y ⋅
⎡ β e − a z (a z − ez ) ⎤
B = 1 + γ − 2γμ ⎢1 + z z
⎥⎦
r2
⎣
When the non-dimensional parameter of the
geometry characteristic is γ << 1, the eigenvalues
of the beam exposed to the constant axial force
will gravitate toward the boundary values, i.e.
γ → 0. From the equation (53) it appears that (the
actual sing „±” appears in the index):
γ → 0 ⇒ Ω + → ω y 1 − μ ∧ Ω − → ∞ , (54)
and from the equation (54):
r
c
= ω y ∧ Ω − → 0 , (55)
ip
ip
When the beam is exposed to the parameter
periodical load Ft = F0 + Ft cosθt developed as
Fourier's series [7] from the equation (38), considering just the first left diagonal element, the limits of
the basic area of instability will be determined as:
1 ⎞
1
⎛
det [Rk ] − xk2 ⎜ F0 ± Ft ⎟[S ] − mθ 2 [D ] = 0 ,
2
4
⎝
⎠
and in the developed form that will be:
,
(58)
B ± B 2 − 4 AC
,
2C
(59)
B ± B 2 − 4 AC
⎧
⎛ 2β e ⎞
A = 1 − (μ ± v )⎨1 + γ ⎜1 + z2 z ⎟ −
r ⎠
⎝
⎩
⎡ 2 β e − (a − ez )2 ⎤ ⎫⎪
− γ (μ ± v )⎢1 + z z 2 z
⎥ ⎬,
r
⎢⎣
⎥⎦ ⎪⎭
⎛ a2 ⎞
C = γ ⎜⎜1 − 2z ⎟⎟ .
⎝ r ⎠
γ → 0 ⇒ Ω+ → ωy
2A
(56)
⎡ β e − a z (a z − ez ) ⎤
B = 1 + γ − 2γ (μ ± v )⎢1 + z z
⎥⎦,
r2
⎣
⎛ a ⎞
C = γ ⎜1 − 2z ⎟.
⎝ r ⎠
(60)
When the dimensionless parameter of geometry characteristic is γ << 1, the beam will be mostly
in the buckling oscillation area. The boundary values for the basic ranges of dynamic instability,
when γ → 0, will be as the following: from the eq.
59, it will be θ∗ = 2ω y 1 − (μ ± v ), and from the
eq. (60) it will be θ ∗ = 2ωϕ
r
.
ip
All this refers to the boundaries of the basic
areas of instability.To determine the adjacent areas
it is necessary to get back to the general equation
(38) and to consider the next diagonal element.
Finally, this equation can be solved in general form
for the critical frequencies. In this case, the numerical values for the mentioned parameters, can
be obtained only numerically.
Mech. Eng. Sci. J., 26 (1), 9–15 (2007)
15
5. CONCLUSION
When the thin-walled beam with an open
cross section of the profile and just one symmetry
axis, is exposed to the eccentric pressure (axial)
load, in certain conditions, the loss of its elastic
(static) stability, i.e. the buckling phenomenon will
appear. Thus, the two cases can be notified as:
1) Buckling in the plane of the minimal radius
of inertia.
2) Traxial buckling caused by torsion (lateral
buckling) [4].
Which case will appear, depends on the cross
sectional geometry and the beam length. When the
same beam is exposed to the parameter periodical
load F = F0 + Ft cosθt in the axial beam direction,
the loss of dynamic stability can appear. That
means that the excitation frequency is in the dynamic load instability area and that the parameter
resonance can notify the following:
1). When the amplitudes of the pressure force
are small enough, the non-stability areas are close
to the frequency:
θ=
2Ω
,
k
(k = 1, 2…),
(54), k is the number of eigen mode shapes, θ is the
load excitation frequency.
2) Combined resonance can appear in the
special case when:
Ω k1 ± Ω k 2 = rθ , (r = 0, 1, 2…),
where Ωk1 and Ωk2 are two roots of the eq. (37),
calculated for the same k; r is the number of harmonics, when the load was developed in Fourier′
series.
REFERENCES
[1] S. P. Timošenko: Teorija elastične stabilnosti, Naučna
knjiga, Beograd, 1952.
[2] D. Rasković: Teorija oscilacija, Naučna knjiga, Beograd,
1957.
[3] D. Rasković, Osnovi matričnog računanja, Naučna knjiga,
Beograd, 1971.
[4] C. Petersen: Stahlbau, Vieveg, Wiesbaden, 1990.
[5] Lj. Radosavljević: Teorija oscilacija, Mašinski fakultet,
Beograd, 1981.
[6] W. Z. Wlassow: Dünnwandige elastische Stäbe, Moskow,
1959.
[7] Grupa avtori, StalÝnìe listov∫e konstrukcii,
Moskva, 1956.
where Ω is the eigenvalue of the thin-walled beam
exposed to the constant pressure force F0, (53) and
Rezime
ANALIZA NA STABILNOSTA NA TENKOYIDNI KONSTRUKCII
Marjan Gavriloski1, Be}ir Hamidi2, Zoran Bogatinoski1
1
Ma{inski fakultet, Univerzitet „Sv. Kiril i Metodij“,
2
Ma{inski fakultet, Univerzitet vo Pri{tina
[email protected]
Klu~ni zborovi: elasti~na i dinami~ka stabilnost; parametar na rezonancija;
sopstvena fleksibilnost na lesni konstrukcii; kriti~na sila na izvivawe
Vo trudot e analiziran problemot na stabilnosta na elasti~nite sistemi kako diskreten stohasti~ki sistem. Vo praktikata nekoi elementi od konstrukcijata se izloèni na aksijalni dinami~ki sili
na pritisok. Ovie optovaruvawa vo dadeni uslovi
moàt da predizvikaat gubewe na elasti~nite osobini, odnosno na dinami~kata stabilnost, koja zavisi
Ma{. in`. nau~. spis., 26 (1), 9‡15 (2007)
od karakterot na optovaruvaweto, geometrijata na
napre~niot presek i dolìnata na elementot. Vo trudot se analizirani lesni konstrukcii so otvoren
napre~en presek so edna oska na simetrija vo uslovi
na rezonancija kako eden od parametrite koj moè da
predizvikuva gubewe na elasti~nosta i dinami~kata
stabilnost.
ISSN 1857–5293
UDK: 658.5
Received: December 17, 2007
Accepted: December 17, 2007
PRODUKTIONSMANAGEMENT IN KLEINEN UND MITTLEREN UNTERNEHMEN
Franc Čuš, Uroš Župerl
Universität Maribor, Fakultät für Maschinenbau,
Smetanova 17, 2000 Maribor, Slovenia
[email protected] / [email protected]
A b s t r a c t: Produktionsunternehmen beschäftigen
vernünftige Leute und werden in aller Regel von klugen
Managern geführt. Wie kommt es dann, dass sich Innovation
und Wandel in erfolgreichen Unternehmen derart schwierig
gestalten? Und warum treten für Produktionsmanagement in
kleinen und mittleren Unternehmen dieselben Muster für
Erfolg und mißerfolg im Lauf der Zeit so deutlich in Erscheinung? Wie kann ein Produktionsmanager wissen, wann evolutionärer Wandel angesagt ist? Maßnahmen des Produktionsmanagements können demnach mit Hilfe analytischer
Methoden bestimmt werden und sind auf Rechnersystemen
implementierbar.
Key words: Management; Produktion; Unternehmen;
Automatisierungskonzepte; Flexibilität; Kosten
1. EINFÜHRUNG
Auf den Weltmärkten ist, nicht zuletzt auch
wegen der nationalen Slüsselposition der Wekzeugmaschinenindustrie, ein harter Konkurrenzkampf der Werkzeugmaschinenhersteller entbrant,
der bereits erhebliche Opfer gefordet hat. Eine
wesentliche Ursache für diesen Konkurenzkampf ist
die Tatsache, daß seit Jahren die Weltproduktion an
Werkzeugmaschinen höher ist als der Bedarf. Daraus
ergibt sich eine generell niedrige Ertragsituation. Da
die Kapzitäten weiterhin deutlich wachsen, ist in
Zukunft eher mit einer Verschärfung dieser
Situation zu rechnen.
Produzierende Unternehmen stehen heute
mehr denn je vor dem Problem, daß die Produkte
den sich ständig ändernden Marktanforderungen
angepaßt werden müssen. Die Orientierung an den
Kundenspezifikationen besitzt höchste Priorität.
Das in hohem Maße dynamische Marktgeschehen
erfordert daher flexible und schnelle Reaktionen
[1, 2].
Diese bedingen ihrerseits eine Verkürzung
der Entwicklungs- und Auftragsdurchlaufzeiten.
Zu diesem Zweck müssen Daten, die während der
Auftragsabwicklung anfallen und Aufschluß über
die Leistungsfähigkeit der beteiligten Unternehmenseinheiten geben, analysiert werden. Hieraus
lassen sich Maßnahmen sowohl für langfristig greifende Anpassungen ableiten.
2. KUNDENNÄHE HAT IHREN PREIS
Als besondere Stärke der Wekzeugindustrie
wird oft ihre Kundennähe herausgestellt. Ihre
Fähigkeit, kunden-spezifische Probleme zu lösen,
hat eine Tradition, die sich aus der engen Zusammenarbeit der Werkzeugmaschinenbauer mit der
Automobilindustrie bei der Planung und Erstellung
von Produktionsanlagen für die Großserienfertigung entwickelte.
Im Zuge fallender Stückzahlen, Losgrößen
und mit dem Aufkommen der NC-Technik wurde
die hochproduktive, aber starre Transferstraße oder
Sondermaschine mehr und mehr durch flexible
Fertigunssysteme ersetzt.
Aus dieser Zusammenarbeit entwickelten sich
die Systemtechniken, und hier entstanden CIMLösungen: Flexible Fertigunssysteme in Verbindung mit rechnergesteuerten Hochregallagern,
automatischer Werkstücktransport und computergesteuerte Werkzeugversorgung, Fertigungsleitrechner und deren Integration in komplexe Vernetzungen unter Einbindung komplexer CAD/CAMSysteme.
Aber die Praxis zeigte, daß mit kundenspezifischen Lösungen wenig Geld zu verdinen war.
18
F. Čuš, U. Župerl
Hohe auftragsbezogene Projektierungs- und
Entwicklungskosten drücken den Deckungsbeitrag
und führen zur Ertragsschwäche, die wir als für
Werkzeugmaschinenindustrie typisch erkannt haben
[1, 3].
Allerdings ist im Bereich der kundenspezifischen Lösungen der Konkurenzdruck – besonders
natürlich der Druck der fernöstlichen Anbieter –
erheblich niedriger. Sicherlich ist dies auch mit ein
Grund dafür, daß sich ein Großteil der Werkzeugmaschinenindustrie in diesem Geschäftsfeld bewegt, dadurch aber auch unter zunehmenden
Konkurenzdruck nationaler
und europäischer
Anbieter gerät (Abb. 1)
Analyse der Fertigungsaufgabe
Analyse der
Arbeitsabläufe
Analyse des Werkstückspektrums
- Geometrie
- Oberflächenqualität
- Werkstoffe
- Spanngeometrie
- Spannart
- Losgröße
- Anzahl der Lose
Anforderungsprofil des
Maschinenkonzeptes
Bearbeitungsverfahren
Flexibilität
Automatisierungsgrad
Systemfähigket
Genauigkeitsanforderungen
- Bearbeitungsverfahren
pro Werkstück
- Stückzeit pro Werkstück
- Aufteilung in HauptNeben- u. Rüstzeiten
- Kosten
Auswahl der Bearbeitungsverfahren
Kombination
- Drehen und Laserhärten
- Drehen, Bohren, Fräsen
und Schleifen in einer Aufspannung
Substitution
- Schleifen/Drehräumen/Hartdrehen/
Harträumen
- wälzfräsen/Fließpressen
gene Strukturen aufweisen. So sind z. B. Flexible
Fertigungssysteme (FFS) mit dem konventionellen
Umfeld – Härterei, Dreherei o.ä., aber auch Werkzeugvoreinstellung, Vorrichtungsbau etc. – zu
synchronisieren.
Die geschilderten Schwachstellen erfordern
neue Strukturen für die Steuerung und Regelung
aller Produktionsaufgaben. Eine funktionale,
zeitliche und organisatorische Segmentierung ist
Voraussetzung dafür, daß die Mängel bezüglich
der Transparenz, der Reaktionszeiten und der
Koordination verschiedener Teilbereiche behoben
werden können[3, 4].
Die Segmentierung kann vertikal z.B. nach
produktbezogenen oder technologischen Gesichtspunkten erfolgen. Sie bedingt gleichzeitig eine
Hierarchisierung und Dezentralisierung der Funktionen, die zur Regelung der Produktion beitragen.
Innerhalb dieser Bereiche sind entsprechend
feinere Regelungen der Abläufe erforderlich. Ein
Eingreifen seitens der Auftragsabwicklungsfunktion ist nur nötig, wenn das Ausregeln von
Störungen durch bereich-und teilbereichsbezogene
Regelungsfunktionen nicht möglich ist (Abb. 2).
Unternehmenserfolg
durch termingerechte
und kostengünstige
Herstellung von
Qualitätsprodukten
- Laser schneiden/
Wasserstrahlschneiden
Einführung von
Einzelsystemen
CAP
BDE
CAQ
MRP
CAD
CAM
Abb. 1. Analyse der Fertigungsaufgabe zur Konzeptfindung
V
P
- Optimierung
(z.B. BOA)
- Erweiterung
(z.B. Leitstand)
- Kopplung
(z.B. CAD/PPS)
P
V
Ein großer Teil von Aufgaben des Produktions
managements wird heute durch Funktionen der
Systeme zur Produktionsplanung und -steuerung
(PPS) unterstützt. Dies zeiht sich z.B. darin, daß die
Systeme eine nur unzureichende Unterstützung der
Werkstattsteuerung bieten, weil sie dirigistich und
in zu groben Zyklen sehr detaillierte Planungsvorgaben machen. Das führt zu einer Steuerung auf
Meisterebene "am PPS-System vorbei", mit der
Folge, daß die Transparenz der Fertigungsabläufe
drastisch sinkt. Dieser Umstand wird durch die
stochastichen Fertigungsabläufe in der Einzel- und
Kleinserienfertigung noch verstärkt.
Erschwerend wirkt sich hier weiterhin aus,
daß die zu koordinierenden Bereiche sehr hetero-
1970
V
M
M
V
3. VORAUSSETZUNGEN FÜR ERFOLGREICHES
PRODUKTIONSMANAGEMENT
reproduzierbare
Meßgrößen
gestufte Regelkreise
nachvollziehbare
Entscheidungen
durchgängiges
anpaßbares
Zielsystem
Optimale Nutzung
vorhandener Systeme
neue Technologie - Laserunterstütztes Drehen
Maschinenkonzept
Gesamtkoordination
1980
P
P
M
R
M
Zeit
1990
V=Vorgaben M=Meßgrößen
P=Produktion R=Regler
Abb. 2. Produktionsmanagement im Wandel der Zeit
4. PRODUKTIONSMANAGEMENT ALS
GESAMTKOORDINATION
Die Leistungsfähigkeit eines Unternehmens
wird durch die Marktanbindung, die Planung und
Vorbereitung sowie die Durchführung bestimmt
Die Marktanbindung wird durch den Vertrieb
realisiert.
Bei Serienfertigern steht die Beobachtung des
Marktes zur Bildung von Produktionsprogrammen
im Vordergrund, bei Auftragsfertigern dagegen die
Auftragsklärung zur Vorbereitung der innerbetrieblichen Auftragsabwicklung.
Mech. Eng. Sci. J., 26 (1), 17–23 (2007)
Produktionsmanagement in kleinen und mittleren Unternehmen
Die Planung und Vorbereitung des eigentlichen Herstellungsprozesses obliegt den Unternehmensbereichen Konstruktion, Arbeitsplanung und
Disposition. Hier werden einerseits aus der Produktbeschreibung des Vertriebes die internen
Arbeitsunterlagen erstellt und andererseits der
Ressourcen- und Materialbedarf für die Durchführung geplant. Zur Durchführung gehört auch
die Regelung der Fertigung und Montage. Die
Aufgabe des Produktionsmanagements besteht in
der Koordination der drei Schwerpunkte Markanbindung, Planung/Vorbereitung und Durchführung.
Die Gesamtkoordination läßt sich in zwei
Ebenen aufteilen: in die Ebene des operativen Produktionsmanagements und in die des analytischen
Produktionsmanagements. Gegenstand der operativen Ebene ist die Auftragsklärung und die innerbetriebliche Auftragsabwicklung, d.h. das "Tagesgeschäft".
Das analytische Produktionsmanagement
setzt auf den Ergebnissen der operativen Ebene
auf. Daten, die um Unternehmen gesammelt werden, geben Aufschluß über die Leistungsfähigkeit
der beteiligten Bereiche und vor allem über die
Wirksamkeit der Koordinationsmaßnahmen.
Eine wesentliche Voraussetzung hierfür sind
Hilfsmittel zur Beurteilung des Leistungsvermögens des Unternehmens. Die Effizienz der Auftragsabwicklung kann man z.B. anhand von Betriebskennlinien beurteilen, woraus sich Maßnahmen ableiten lassen, die zur Verbesserung des
Produktionsmanagements beitragen.
19
daß nur diejenigen Produkte in den Mengen zu den
Terminen angefertigt werden, zu denen sie tatsächlich auch benötigt werden
6. MAßNAHMEN IM RAHMEN DES
ANALYTISCHEN PRODUKTIONMANAGEMENT
Wichtigste Aufgabe des Produktionsmanagements ist die Vorgabe von Zielen, die es den operativen Bereichen ermöglichen, ihren Beitrag zur
Erreichung des Gesamtoptimums zu beurteilen [3,
4, 5].
Die Suche nach dem Gesamtoptimum
entspricht einer Gewichtung der Unternehmensziele. Allerdings müssen diese strategischen Ziele
in solche Teilziele zerlegt werden, die von den
jeweiligen Teilbereichen auch direkt beeinflußbar
sind. Hier findet sich der Ansatz der gestuften
Regelkreise wieder.
Einsatz des Menschen
Motivation aller Beschäftigten durch:
- Flexibilität
- sicheres Umfeld
- prozeßorientierte Entlohnung
und Beurteilung
Verantwortung
- an Prozessen orientieren
- delegieren
Schulung aller Beschäftigten:
5. MAßNAHMEN IM RAHMEN DES
OPERATIVEN PRODUKTIONSMANAGEMENT
Bisher wurde diese Aufgabe im betrachteten
Beispiele in der Praxis konkret wie folgt abgewickelt. In der Auftragsdisposition wurde unter
Berücksichtigung von Vergangenheitswerten und
Marktindikatoren – u.a. den eingegangenen
Kundenaufträgen – ein Produktionsprogramm
erstellt. Auf dieser Grundlage wurden die
Beschaffungsund Fertigungsvorgänge ausgelöst.
Wie sich jedoch zeigte, konnten trotz der
"optimalen" Losgrößen nicht alle Kunden direkt
aus dem Lager beliefert werden.
Heute wird die Auftrags- und Fertigungsdisposition nicht mehr getrennt und nacheinander
durchlaufen, sondern gezielt koordiniert.
Die Umsetzung dieser Maßnahme ging einher
mit der Umstellung von der Losgrößenfertigung
auf die Just-In-Time(JIT)-Fertigung. JIT bedeutet,
Ma{. in`. nau~. spis., 26 (1), 17‡23 (2007)
- prozeßorientiertes Denken
- Kommunikation
- Kooperation
Führen statt Managen
Abb. 3. Gestaltungsempfelungen: Mensch
Die Voraussetzung für diese gestuften Regelkreise ist die Entwicklung einer Zielhierarchie, aus
der sich die jeweiligen Führungsgrößen ableiten
lassen (Abb 3). Da die Teilziele voneinander
abhängen, müssen Hilfsmittel zu deren Einstellung
herangezogen werden.
7. EDV – UNTERSTÜTZUNG DER
PRODUKTIONSMANAGEMENTS
Wie anhand bereits ausgeführt wurde, sind
die Charakteristika der Gesamtkoordination repro-
20
duzierbare Meßgrößen, gestufte Regelkreise,
nachvollziehbare Entscheidungen und ein durchgängiges, anpaßbares Zielsystem.
Die Konsequenz aus diesen Forderungen ist
eine Dezentralisierung von Unternehmensfunktionen, um einerseits eine hohe Reaktionsfähigkeit
durch die Zusammenfassung von Führungskompetenz und Regelungsentscheidung zu schaffen und
andererseits die Systemstruktur schneller und mit
weniger Aufwand den sich ändernden Anforderungen anpassen zu können.
Der erste Schritt in diese Richtung sind flexible
Leitstands-systeme, die die Entscheidungsfindung
unterstützen. Diese Tools sammeln und verdichten
Daten aus dem Vertrieb, den Engineering-Bereichen,
der Materialwirtschaft sowie der Fertigung und
Montage. Auf dieser Grundlage werden Informationen aufbereitet und bewertet, wodurch die Ableitung
von Maßnahmen erleichtert wird.
So unterstützt ein System zur Auftragsabwicklung die Leitstelle bei der Planung des Produktionsprogramms, der Grobplanung von Kundenaufträgen, der Erstellung von Angeboten sowie
der Simulation von Anfragen. Darüber hinaus
werden Sonderfertigungen und Erstplanungen in
die Betrachtung einbezogen.
gelte: Je kleiner der Fertigungsbetrieb, desto
kleiner ist im allgemeinen auch die Anzahl der pro
Auftrag zu fertigenden Werkstücke. Das bedeutet,
daß bei der Vielzahl kleiner Fertigungsbetriebe die
Forderung nach hoher Flexibilität Vorrang hat um
den schnel wechselnden Fertigunsaufgaben zu
entsprechen [5, 6, 7].
Dieser hohe Flexibilitätanspruch prägt naturlich die Organisation eines klein- oder mittelständisches Betriebes in einer ganz anderen Weise
als im Großbetrieb.
Beim klein Betrieb dominiert das Prinzip der
Werksttat-fertigung mit ihren besonderen Merkmalennbezug auf den Einsatzvon qualifizierten
Arbeitskräften und Universal- beziehugsweise
Mehrzweck-Werkzeugmaschinen.
Für die Vielzahl dieser Betriebe muß es doch
ebenfalls Konzepte für eine »Fabrik mit Zukunft«
geben. Konzepte die offensichtlich anders aussehen müssen als die Systemkonzepte der Großindustrie (Abb. 4)
Gestaltung der Organisation
Auf Wertschöpfung
konzentrieren
Schlanke Organisation schaffen
8. WERKSTATTORIENTIERTE PRODUKTION
Das Feld der werkstarttorientierten Produktion liegt also – von der Fertigungsaufgabe her
bedingt – im Bereich der Einzelteil-, Klein- und bis
hin zur Mittelserienfertigung. Typische Fertigungsbetriebe, die sich mit diesen Serien-größen befassen,
sind die
– Werkzeug- und Formenbauer,
– Vorrichtungsfertiger,
– Sondermaschinenhersteller,
– Prototypenfertiger,
– Unterlieferanten für Großbetriebe.
Vor allem die letzeren gewinnen immer
stärker an bedeutung, seitdem sich über die Automobilindustrie hinaus auch andere Industriezweige
dem Just-in-time-Prinzip verschrieben haben und
die Fertigungstiefe durch teilweise Fremdvergabe
ihrer Produktion verringern. Untersucht man die
Struktur der metallverarbeitenden Industrie, so
existieren Betriebe, deren Merheit den Kleinbetrieben zuzurechnen ist. Eine Größenordnung
also, bei der es sich lohnt, nach ihren besonderen
Bedürfnissen zu fragen. Allen gemeinsam ist, daß
es sich bei diesen Betrieben um relativ kleine
Unternehmen handelt. Für sie darf als Faustregel
Räumliche und funktionale
Integration realisieren
- Schnittstellen reduzieren
- übergreifende Teams bilden
- Tätigkeiten ganzheitlich gestalten
- selbststeuernde Regelkreise einführen
Hilfsmittel / Systeme
- von Mitarbeitern initiieren
- am Prozeß ausrichten
Produkt- und Prozeßgestaltung parallelisieren
Abb. 4. Gestaltungsepfelungen: Organisation
9. AUTOMATISIERUNG DER EINZELTEILUND KLEINSERIENFERTIGUNG
Automatisierungskonzepte für den mitelstäandisches Bereich, also für die Einzelteil- und
Kleinserienfertigung, müssen sich auf den qualifizierten Facharbeiter ausrichtenund sich im
Weksttatbereich maschinennah ansiedeln.
Dies bestätigt auch eine Marktuntersucung
des ITW der TH Darmstadt, die sich unter anderem
auch auf den Stand der Programmiertechnik in
Mech. Eng. Sci. J., 26 (1), 17–23 (2007)
Abhängigkeit von der Betriebsgröße bezog [10].
Danach dominierte in den Kleinbetrieben eindeutig
die Programmierung an der NC-Maschine direkt.
Und wenn man bedenkt, daß die CNCMaschine und ihre Programmierung den Ausgangund Kernpunkt eines jeden Automatisierungskonzepts darstellen, dann bestätigt diese Untersuchung
klar, daß weiterführende Automatisierungskonzepte für die Klein- und Mittelindustrie in der Tat
Werkstattbereich ansetzen müssen.
10. KOMBBINIERTES WERKZEUGUND TECNOLOGIEMANAGEMENT
Immer mehr Anwender verlangen eine kombinierte Erstellung exakter Werkzeuge- und
bearbeitungsdaten. Grundgedanke ist, daß in Zuordnung bzw. Abhängigkeit vom Werkzeug optimierte
technologische Daten zur Verfügung gestellt
werden. Entsprechende Programmpakete stützen
sich auf Leistungfähige Datenbanken.
Die optimierung von schnittdaten und
Werkzeugfluß führt zu einer nicht unerheblicher
Erhöhung der Maschinennutzung und der Werkstückqualität. Integrierte Module zur Erfassung
von Maschinendaten (MDE) und Betriebsdaten
(BDE) unterstützen bei der Wirkungsvollen Ausnutzung leistungsfähiger Werkzeugmaschinen.
Dem Anwender muß die Möglichkeit zur Verfügungstehen, auf die Ergebnisse von Zerspanungsprüfungen zugreifen zu können, durch welche die
unterschiedlichen Schneidstoffe ganzheitlich und
praxisbezogen charakterisiert werden.
21
Flexibilität im Vordergrund: das schnelle Umrüsten von einer Bearbeitungsaufgabe zur nächsten,
das Spannen des Roteils ohne Vorrichtung direkt auf
den Maschinentisch, das Arbeiten ohne Palletenorganisation und nicht zultzt das werkstattnahe
Programmieren, häufig durch den Facharbeiter an
der Maschine selbst. Hier muß die Zeitspanne vom
Eingang des Auftrags bis zur Fertigstellung des
Werkstücks möglichst klein werden. Es gilt den
Weg von der Zeichnung bis zum fertigen Werkstück
so kurz wie möglich zu halten. Dies verbietet eine
Fertigungsorganisation mit spezialisierten sequentiellen Arbeitsgängen [5, 6, 8].
Es ensteht eine Fertigungsorganisation, bei
der Mensch in der Wekstatt im Mittelpunkt steht.
Hier werden die Fähigkeiten und die Kenntnisse
des Fertigungstechnikers voll ausgeschöpft, seine
Qualifikation voll gefordet (Abb. 5).
11. FLEXIBEL DURCH
WERKSTATTKOMPETENZ
Je größer die Losgröße, desto wichtiger ist die
hohe Produktivität der Werkzeugmaschine. Hier
kommt es auf Sekundenbruchteile an. Hohe Zerspanleistung, kurze Nebenzeiten, Rüsten während
der Hauptzeit der Hauptzeit sind die Wesentlichen
Forderungen an die Wekzeugmaschine. Dies ergibt
eine arbeitsteilige Fertigungsorganisation im
Taylorschen Sinn, bei derdie Werkstatt zum ausführenden Organ vorgeplanter, fester Arbeitsanweisungen und optimierter CNC-Programme wird
und bei der die umfassenden zerspanungstechnischen Kenntnisse des Facharbeiters in der
Werkstatt nicht gefragt sind.
Ganz andere Anforderungen stellt dagegen
die Fertigung kleiner Losgrößen. Hier steht die
Ma{. in`. nau~. spis., 26 (1), 17‡23 (2007)
Abb. 5. Organisatorische Ansätze und Anforderungen an
Mitarbeiter
12.WELCHEN NUTZEN HAT DAS
ZERTIFIZIERTE UNTERNEHMEN
Ein zertifiziertes QM-System dient zur
Vertiefung des Vertrauensverhältnisses zwischen
Kunden und Liferanten. Die Erwartungen – und
internen Effekte – beim Lieferanten sind dagegen
aus der Philosophie der ISO 9000 abzuleiten.
Die größten Erwartungen richten sich auf
Verbesserungen in den eigenen Abläufen. Hierbei
22
sollen die Anregungen, Hinweise und Vorschläge,
die die Normenreihe vorgibt, mit den eigenen
Abläufen
verglichen und
die
erkannten
Schwachstellen beseitigt werden.
Die Vorbereitung auf die Zertifizierung ist
immer dann mit erheblichen Kosten Verbunden,
wenn eine solche Bewertung und Verbesserung der
Abläufe, der Organisation und der Prozesse
Längere Zeit nicht durchgeführt wurde [8, 9, 10].
Die Gründe für nicht erfühlte Erwartungen
sind vielfältig und häufig in zu hohen Erwartungen
und in der unzureichenden Konsquenz der
Umsetzung zu finden. Die gennanten Erwartungen
suggerieren bei oberflächlicher Betrachtung mit
dem Zertifikat ein Allheilmittel für alle Probleme
[7]. Dieses Mittel scheint bei richtiger Anwendung
dem Kunden seine Verantwortung für die
Lieferantenbeziehung und dem Lieferanten seine
Verantwortung für die Gestaltung seines Betriebes
abzunehmen.
13. ZUSAMMENFASSUNG
Die nur unzureichende Erreichung von Zielen
des Produktionsmanagements zeigt, daß Maßnahmen im Sinne von Gesamtkoordination durch
Regelung der an der Auftragsabwicklung beteiligten
Bereiche erforderlich sind [11]. Dazu sind
verschiedene Bereiche miteinander zu verknüpfen.
Außerdem müssen konkurrierende Ziele abgestimmt werden.
Basis des erfolgreichen Produktionsmanagements ist die Segmentierung und damit verbunden
die Hierarchisierung und Dezentralisierung von
Funktionen, die zur Regelung der Abläufe in der
Produktion erforderlich sind. Im einzelnen ergeben
sich folgende Voraussetzungen für Produktionsmanagement zur Steigerung des Unternehmenserfolges, der durch die termingerechte und kostengünstige Herstellung von Qualitätsprodukten bestimmt
wird.
Maßnahmen des Produktionsmanagements
können demnach mit Hilfe analytischer Methoden
bestimmt werden und sind auf Rechnersystemen
implementierbar [12]. Es wurde gezeigt, daß sich
bei gezieltem Einsatz solcher Maßnahmen die
Effizienz der Produktionsabläufe und damit der
Unternehmenserfolg steigern lassen.
SCHRIFTUM
[1] Branko Katalinić: Megatrends in der Automatisierung der
Produktion, Elektrotechnik und Informationstechnik,
Zeitschrift des Österreichischen Verbandes für Elektrotechnik, e & I, 112. Jg. (1995, Heft 4, pp. 169–171,
Springer Verlag, ISSN 0932-383X Wien / New York,
1994.
[2] J. Balič, Z. Živec, F. Čuš: Model of a universal manufacturing interface in CIM for small- and medium-sized
companies, Journal of Materials Processing Technology.
Amsterdam; Oxford; New York; Tokyo., 52 (1995); S.
103–114, ISSN 0924-0136.
[3] F. Čuš: Automatisches Daten – Erfassungssystem für Zerspanungen, Werkstatt und Betrieb, 120 (1987) S. 923–
926, Carl Hanser Verlag, München.
[4] Uroš Župerl, Franc Čuš: Določevanje značilnih tehnoloških in gospodarskih parametrov med postopkom odrezovanja – A determination of the characteristic technological and economic parameters during metal cutting. Stroj.
vestn., letn. 50, št. 5, str. 252–266 (2004),.
[5] Valentina Gečevska, Franc Čuš, Vladimir Dukovski,
Mikolaj Kuzinovski: Modelling of manufacturing activities by process planning knowledge representation. Int. j.
simul. model., Vol. 5, No 2, pp. 69–81 (June 2006).
[6] Jože Balič, Franc Čuš: Intelligent modelling in manufacturing. Journal of achievements in materials and manufacturing engineering, Vol. 24, Iss. 1, pp. 340–348 (Sep.
2007).
[7] Franc Čuš: Prihaja prelomno obdobje izobraževanja inženirjev : izobraževanje inženirjev. Del 1. IRT 3000, letn. 1,
4, str. 33–35 (2006).
[8] Peter Drucker, Isao Nakauchi: Die globale Herausforderung, ECON, 1996.
[9] Cornelius Herstatt, Birgit Verworn: Management der
fruehen Innovationsphasen, Gabler, Wisbaden, 2003.
[10] Alfred Herbert Fritz: Fertigungstechnik, 7. Auflage,
Springer Verlag Berlin Heidelberg, 2006.
[11] Franc Čuš, Matjaž Milfelner, Uroš Župerl: Prestrukturiranje v smeri višjih tehnoloških stopenj z optimiranjem
procesov obdelave. V: Proceedings of the 23rd International Scientific Conference on Organizational Science
Development, Slovenia, Portorož, March, 24th – 26th
2004. Management, Knowledge and EU. Kranj: Moderna
organizacija = Modern Organization, 2004, pp. 10–16.
[12] Franc Čuš, Uroš Župerl, Valentina Gečevska: Simulation
of complex machining process by adaptive network based
inference system. V: Abele, Eberhard. (ur.), Udiljak,
Toma (ur.), Ciglar, Damir (ur.). 11th International Scientific Conference on Production Engineering – CIM 2007,
June 13–17, 2007, Biograd, Croatia. Computer integrated
manufacturiong and high speed milling. Zagreb: Hrvatska
udruga proizvodnog strojarstva, cop. 2007, str. 103–106.
Mech. Eng. Sci. J., 26 (1), 17–23 (2007)
23
Rezime
PROIZVODSTVEN MENAXMENT VO MALITE I SREDNI PRETPRIJATIJA
Franc Čuš, Uroš Župerl
Universität Maribor, Fakultät für Maschinenbau,
Smetanova 17, 2000 Maribor, Slovenia
[email protected] / [email protected]
Klu~ni zborovi: menaxment; proizvodstvo; kompanija; avtomatizirani koncepti; fleksibilnost;
tro{oci
Uspe{nosta na sovremenite proizvodni kompanii naj~esto se dolì na uspe{en menaxment i vraboteni kreativni lu|e. Vo trudot e napraven obid da se
dadat nasoki za mo`ni odgovori na slednite pra{awa: Kako inovativnite promeni vo uspe{nite kompanii se integriraat vo politikata na menaxmentot so
streme` da se postigne pogolem uspeh? Po koi pre-
Ma{. in`. nau~. spis., 26 (1), 17‡23 (2007)
poznatlivi modeli za uspeh treba da se vodi proizvodstveniot menaxment na malite i sredni kompanii?
Kako menaxmentot da prepoznae koga da se vovedat
evolutivni promeni vo upravuvaweto so kompanijata? Vo trudot se dadeni mo`ni merki koi e potrebno
da gi prezema proizvodniot menaxment bazirani na
implementirawe analiti~ki informati~ki metodi.
ISSN 1857–5293
UDK: 621.65 : 621.757
Received: November 28, 2007
Accepted: December 11, 2007
Professional paper
PRODUCT CONFIGURATORS AS A TOOL FOR INCREASING COMPETITIVENESS
OF SMALL AND MEDIUM ENTERPRISES
Zoran Anišić1, Valentina Gečevska2
1
Faculty of Technical Sciences, Department for Industrial Engineering and Management Department,
University of Novi Sad, Trg Dositeja Obradovića 6, Serbia
2
[email protected] // url: www.ftn.ns.ac.yu,
A b s t r a c t: The paper will show some practical results of the implementation of mass customization in small
companies. Two production programs will be presented, suitable for involving customization in the particular market segments. The first industry solution deals with a furniture production program for shops and boutiques where strategy enables a variation of available modules, dimensions, colors and
shapes, while the second industry solution offers a possibility to
design and personalize gates, fences, balcony rails and stair rails
made of wrought iron. In both cases, modules used for customization are prefabricated in mass production. The paper will focus on
the developed product configurators for the above mentioned
production programs concerning the product structure, choosing
relevant product features, programming language and some early
results of their implementation.
Key words: mass customization; product configurators;
group technology
1. INTRODUCTION
1.1. Product Configurators
Recently, a new set of design solutions, called
Product Configurators (PC), have become significant in addressing many of the design issues related to mass customization [1, 2, 5]. They are
systems that create, maintain, and use electronic
product models that allow a complete definition of
all possible product options and variation combinations, with a minimum of data entries. This capability is essential for the companies offering unique
configurations to satisfy specific customer needs
[1, 3, 4]. Configuration is “…the construction of a
physical system according to specifications by selecting, parameterizing, positioning and assembling
instances of suitable existing component types from
a given catalog” [2].
Despite a huge number of variations, the electronic systems with a mass customization interaction platform consist of three main components:
• The core configuration software presents the
possible variations and guides the user through
the configuration process, asking questions or
providing design options. Consistency and manufacturability are also checked at this stage.
• A feedback tool is responsible for presenting
the configuration. Feedback information for a
design variant can be given as visualization and
in other forms (e.g. price information, functionality test etc.) and is the basis for the trialand-error learning of the user.
• Analyzing tools finally translate a customer
specific order into lists of material, construction plans, and work schedules. They further
transmit the configuration to manufacturing or
other departments.
One of the basic division among configurator
solutions is the type of interaction with customers
[6]. Figure 1 shows online and offline options with
possibilities of different programming language
realization.
Product configurators in conjunctions with
CAD/CAM systems and flexible automation (efactories of the future) have the potentials to
achieve the goals of data management systems with
regards to the rapid product development. These
product configurators have emerged as the newest
design tools for 21st century product development
and will play a key role in realizing the goals of
mass customization.
26
Z. Anišić, V. Gečevska
OFFLINE CONFIGURATORS
CD - ROM
DVD - ROM
MOBILE COMPUTING
ONLINE CONFIGURATORS
FROM THE SERVER SIDE
SA SERVERSKE STRANE
FROM THE CLIENT
SA KORISNIČKE STRANE
HTML
JAVA
XML
PLUGIN
PHP
GUI
ASP/CGI
2. Product analysis. Analysing products and
eventually life cycle systems. Redesigning/restructuring products. Structuring and formalising knowledge about the products and related life
cycle systems in a product variant master.
Tools: List of features and product variant
master.
EJB/(JSP) JAVA
WAP (MOBIL)
Fig. 1. Available technologies for configurator the design
Since, CAD is essentially the design portal for
products, software directly translates customer requirements into design concepts in the CAD system if necessary. Product configurators feel this
need to link the customer requirements to the design stage. Designers or end customers use product
configurators to create a product from a set of predefined options or variables. Configurators range
from simple tools within limited options to complex rules based systems that bring together all the
parts, products and processes to meet the customer
specifications.
The procedure for building product configurator systems is based on several theoretical domains
including:
• Modeling concepts – based on object oriented
modeling,
• Product analysis – dealing with the transformation of product knowledge into a product
model,
• Organizational aspects – how to organize the
development of product configuration systems,
• Development of business process – how to
identify and redesign a new business process.
3. Object oriented analysis. Creation of object classes and structures. Description of object
classes on CRC-cards. Definition of user interface.
Other requirements to the IT solution.
Tools: Use cases, class diagrams and CRCcards.
4. Object oriented design. Selection of configuration software. Defining and further developing the OOA-model for the selected configuration
software. Requirements specification for the programming including user interface, integration to
other IT systems.
5. Programming. Programming the system
based on the model. Testing the configuration system.
6. Implementation. Implementation of the
product configuration system in the organisation.
Traning users of the system, and further training of
the people responsible for maintaining the product
configuration system.
7. Maintenance. Maintenance and further
development of the product and product related
models.
1.2. A procedure for building configurator systems
2. INDUSTRY SOLUTION
The procedure for building configurator systems for mass customization, takes few steps as
follows:
This chapter deals with building and implementation of the configurator systems on two production programs in domestic companies.
1. Process analysis. Analysis of the existing
specification process (AS-IS), statement of the
functional requirements to the process. Design of
the future specification process (TO BE). Overall
definition of the product configuration system to
support the process
Tools: flow charts, Activity Chain, Model,
key numbers, problem matrix, SWOT, list of functional describing characteristics and gap analysis.
2.1. Furniture for shops and salons
The first example, presents the successful application of the MC concept on production program of furniture for shops «ŽAKO» Stara Moravica. The production program is developed using
the modular principle, and the operational groups
of parts are formed, giving them max. level of customization according to technological capabilities
Mech. Eng. Sci. J., 26 (1), 25–32 (2007)
27
Product configurators as a tool for increasing competitiveness of small and medium enterprises
of manufacturer. Table 1 shows ten operational
groups of parts from which one can easily build a
wall shelf, as well as attributes allowed to be customized.
Figure 2 shows the structural scheme of the
complex product – product master, capable to en-
compass all modules (subassemblies and parts) and
their operational groups. The configurator system
for this product is developed in offline internet surrounding, and Figuures 3 and 4 present one segment of the customized wall shelf.
Table 1
Operational groups of parts of the furniture
OG1 Metal bar
OG2 Wall clamp
Attributes:
Dimensions:
Color:
Attributes:
Color:
OG6 Wooden ball
Attributes:
Dimensions:
Color:
OG3 Adjustable foot
Attributes:
Color:
OG7 Connect. bar
Attributes:
Dimensions:
Color:
OG4 Shelf carrier
OG5 Shelf
Attributes:
Dimensions:
Color:
OG8 Stand carrier
Attributes:
Dimensions:
Color:
Attributes:
Dimensions:
Material:
Color:
OG9 Stand
OG10 Cons. shelf carrier
Attributes:
Dimensions:
Color:
Attributes:
Dimensions:
Color:
1
1 3
STABLO
PS STUBA 1 M
1 1
1
ČEP
1
CORK
METAL BAR
SUB M.BAR
SVETLO
LIGHT
COVER
1 1
WALL CLAMP
PROIZVOD
PRODUCT
VEZNI EL. 1
1
CONNECT.EL.
STOPALO
1 1
NOSAČ1 1
FOOT
CARRIER 1
PS POLICE 1 M
ID[
SUB SHELF
POLICA
1 2
B
1
SHELF
1 1
1
[ TENDER 1 4
1
1
STAND
1
1
Fig. 2. Structural scheme of wall shelf for shops and salons – product master
Ma{. in`. nau~. spis., 26 (1), 25‡32 (2007)
28
Fig. 3. Product configurator – furniture for shops and salons
Fig. 4. Report preview of the confihured product – ready for printing of e-mailing
Mech. Eng. Sci. J., 26 (1), 25–32 (2007)
2.2. Wrought iron products
Assortment of products made from wrought
iron is quite wide, but the main representatives are
(Fig. 5):
• gates,
• balcony rails,
• fences,
• stair rails,
• furniture and other objects.
Products made from wrought iron have several centuries long history, and traditional technology assumes completely hand forged manufacturing. Recently, there is a huge number of mass produced elements present on the market, manufactured on high productive forging machines, available at every large supplier of building material.
The emerged situation opened the possibilities of
applying the MC concept in this area, though designing customized products from prefabricated
elements, is slightly more expensive than the classic metalwork made from steel shapes.
Current situation in this field on the market
and the prices are given bellow (material and manual work included):
• products made from steel shapes, the price
is 100 €/m2,
• products made from prefabricated forged
elements, the price is 200 €/m2,
• taylormade products, completely hand forged, the price is 600 €/m2,
which has opened possibilities for new niche markets, similar to other fields (Fig. 6).
Gates
Balcony rails
Fences
Stair rails
Fig. 5. Basic products from wrought iron
Ma{. in`. nau~. spis., 26 (1), 25‡32 (2007)
29
30
Fig. 6. Mass produced elements made with forging machines
2.3. Building product configurator
Due to limitation, the paper will cover only
the principal development of the gates, as a part of
the production program. After the anlysis of
available gates made from wrought iron, four basic
types are pointed out:
• sliding gates,
• one wing gates,
• two wing gates,
• four wing gates
Figure 7 shows sketches of basic gate types,
which are at the same time complex products
representatives.
In addition, seven operational groups of parts
are given, with the minor part of the total number
of elements, together with parameterized sketches
for the complex representative of the group, used
for designing all four types of gates (Tab. 2).
Designing the gate can be easily performed
using the drag and drop technique. The customer
just has to select the desired element from the correspondent operational group and to drag it to the
field in the chosen type of the gate. The product
configurator system performs positioning of the
element, and/or the necessary number of instances
that have to be copied, having in mind the standard
distance between elements of 120 mm and the
overall wide of the gate defined by the customer.
The product configurator is built in Delphi programming language, in offline mode, according to
the category of the product. It is expected that the
customer download configurator file, perform customization and upload the desired solution for further quotation and adjustment.
Sliding gate
One wing gate
Two wing gate
Four wing gate
Fig. 7. Basic types of gates
Mech. Eng. Sci. J., 26 (1), 25–32 (2007)
31
Table 2
Operational group of parts from the wrought iron
p11
p12
p21
p31
p22
p32
Complex product
p13
p23
p33 ….
C-CURVES
VERT.BARS
S-CURVES
SHARP END
Operational group of parts
OG1
OG2
OG3
OG4
p51
p52
OG5
p61
p62
OG6
HINGES
LOCKS
CENT. DETAIL
p41
TWO WING GATE
COMPLEX PRODUCT REPRESENTATIVE
1 – Sharp ends, 2 – S-curves, 3 –Vert.bars, 4 – Bottom area,
5 – Central detail, 6 – Door lock, 7 – Hinges
CUSTOMIZED TWO WING GATE
Designing the product using elements from correspodent
operational groups
p71
p72 .....
OG7
3. CONCLUSION
From the given examples, it can be concluded
that for a large number of production programs
certain suitable segments of the market could be
found, for applying the MC concept. It is a relatively narrow market niche positioned between the
cheapest products, mass produced and very expenMa{. in`. nau~. spis., 26 (1), 25‡32 (2007)
sive taylor made products, manufactured on special
demand. The constant and progressive development of IT, especially in the domain of product
design, process planning and control, necessary for
the MC sustainability, opens possibilities for widening this market segment, giving perspective for
the future.
32
Besides the mentioned market situation, product
configurator development is very important regardless of the applied level MC concept. The product
configurator enables easily processing a large number of inquiries and forwards them to the production system for further designing of nonstandard
parts and process plans for manufacturing. Visualization of the product through showing possible modification on computers impresses customers and
they are more readily for buying even the possibility for customization is minimal.
The fact is, that at this moment, only large international leading companies have power for implementation of the MC concept but small and medium enterprises could have benefits even now,
through the application of certain segments concerning configuration and visualization of products. Introduction of the approach and refreshment
of the marketing promotion – offering personalized
products will strengthen their competitive position
on the market for surely.
Having in mind, that the configurators described in the paper have been in use only few
months, there is no valid reverse information concerning behavior of the customers or achieved
benefits for the manufacturers. If is just left to
track every single request in order to improve effects.
4. REFERENCES
[1] A. Karlsson: Assembly Initiated Production – A Strategy
for Mass Customisation, Utilising Modular, Hybrid
Automatic Production Systems, Assembly Automation,
Vol. 22, No 3, pp. 239–247 (2002) (ISSN 0144-5154).
[2] M. M. Tseng, F. T. Piller: The Customer Centric Enterprise: Advantages in Mass Customization & Personalization, Springer: New York/Berlin (2003).
[3] I. Ćosić, Z. Anišić, B. Lalić: Group Technology as a Basis
for Mass Customisation, Proceeding of the 14th DAAAM
INTERNATIONAL SYMPOSIUM "Intelligent Manufacturing & Automation: Focus on Reconstruction and Development", Sarajevo, Bosnia (2003).
[4] Z. Anišić, I. Ćosić, B. Lalić: Some Cases in Applying
Concept of MC in Production System Designing, Proceeding of the International Conference on Mass Customization and Personalization Theory and Practice in
Central Europe, Rzeszow, Poland (2004).
[5] Z. Anišić, I. Ćosić, B. Lalić: Mass Customization and the
Process of Production Systems Designing – Case Study,
Proceeding of the International Conference “Manufacturing and Management in 21st century”, Ohrid, Republic of Macedonia (2004).
[6] Z. Anišić, I. Ćosić, B. Lalić: The Choice of the Optimal
Product Configurator in Mass Customization Strategy,
Proceeding of 16th DAAAM INTERNATIONAL SYMPOSIUM "Intelligent Manufacturing & Automation: Zoung
Researches and Scientists", pp. 9–11, Opatija, Croatia.
(2005).
Rezime
KONFIGURATORI NA PROIZVOD KAKO ALAT ZA PODOBRUVAWE
NA KONKURENTNOSTA NA MALI I SREDNI KOMPANII
Zoran Ani{i}1, Valentina Ge~evska2
1
Fakultet tehni~kih nauka, Otsek za industrijsko inèwerstvo i menaxment,
Univerzitet u Novom Sadu, Trg Dositeja Obradovi¢a 6, Srbija
2
Ma{inski fakultet, Univerzitet „Sv. Kiril i Metodij“,
[email protected] / url: www.ftn.ns.ac.yu,
Klu~ni zborovi: strategija mass customization; proizvodni konfiguratori; grupna tehnologija
Vo ovoj trud e daden prikaz na prakti~nin rezultati od implementacija na strategijata „mass customization“ (proizvodi za {iroka potro{uva~ka spored barawata na kupuva~ite) vo mali kompanii. Prikaàni se dve razli~ni proizvodni programi pogodni
za voveduvawe na strategijata „mass customization“ vo
pazarnite segmenti koi tie gi pokrivaat. Prvata
proizvodna programa se odnesuva na proizvodstvoto
na mebel, kade primenlivosta na strategijata „mass
customization“ se bazira na varijabilnosta i modular-
nosta na proizvodite konfigurirani preku dimenzii,
boi, formi, a vtorata proizvodna programa ja prikaùva primenlivosta na istata strategija kaj proizvodi od kovano èlezo. Vo dvata slu~aja modularnosta e
osnova za masovno proizvodtsvo.
Trudot ja prikaùva implementacijata na strategijata „mass customization“ preku razvoj na proizvodni konfiguratori za dvete analizirani proizvodni
programi, konfiguratori koi se generirani vo soglasnost so strukturata i formite na proizvodite.
Mech. Eng. Sci. J., 26 (1), 25–32 (2007)
ISSN 1857–5293
UDK: 621.039 : 004.6 (497.7)
Received: November 5, 2007
Accepted: November 6, 2007
Professional paper
THE ROLE OF THE NATIONAL INIS CENTER IN PRESENTING MACEDONIAN
NUCLEAR AND NUCLEAR RELATED SCIENCES
Marija Sejmenova-Gichevska
National and University Library “St. Kliment Ohridski”,
MK-1000 Skopje, Republic of Macedonia
[email protected]
A b s t r a c t: The Republic of Macedonia is 95th
Member State of INIS and its participation in this cooperative
decentralized system started in 1996 when the Macedonian
INIS Center was established to be operated by the National
and University Library “Kliment Ohridski” in Skopje. The
main objective of this study is to give an overview of the Macedonian nuclear and nuclear related scientific thought presented in the INIS Database. A statistical analysis of the Macedonian INIS Center’s contribution to the INIS Database for
the period of its constitution to 2006, by quantifying and reviewing the language, publication type and INIS subject categories of the submitted records is presented.
Key words: INIS; Macedonian INIS Center; INIS Database
INTRODUCTION
Macedonian focal point to the INIS System –
the National INIS Center, operates within the
framework of the National and University Library
“Kliment Ohridski” – Skopje. Its acting is in close
relationship with the Macedonian Ministry of Education and Science, which is a National coordinator
of the whole activities in Macedonia, connected to
IAEA.
INIS (International Nuclear Information System) is a bibliographic database covering the
worldwide-published literature in nuclear research
and technology, as well as collecting the associating full texts of non-conventional literature. Since
INIS is based on international cooperation, i.e. at
present 117 countries and 23 international organizations have participated in building the INIS Database, the main Macedonian INIS Centre’s task is
creating information of the scientific-research activities in Macedonia in the domain of sustainable
application of nuclear science and technology.
Thus, the achievements of Macedonian respective
scientists and scholars are being presented in the
global network as INIS is, which not only ensures
access to the worldwide scientific and technical
literature but it is a base for preservation and exchange of nuclear knowledge.
MACEDONIAN INPUT
TO THE INIS DATABASE
A bibliometric study of the Macedonian nuclear and nuclear related scientific thought presented in the INIS Database is performed. The objective of this study is to quantify and analyze bibliographic records prepared by the Macedonian
INIS Center, with particular emphasis on language,
publication type and INIS subject categories of the
relevant records.
The analysis is carried out on the basis of
searches and retrievals in the INIS Database on
CD-ROM. The period covered in the analysis is
1980–2006/12 and includes all published and input
items into the INIS Database until that date. Taking into consideration that the Macedonian INIS
Center was established in 1996 and 1997 was its
first imputing year, the following period, from
1980 to December 2006, is considered relevant for
this analysis.
The total number of records of the Macedonian INIS Center processed and submitted to the
INIS Database for the above mentioned period is
1023.
34
`M. Sejmenova-Gichevska
1. Language
The Language of Macedonian input is Macedonian 55%, English 42%, or both Macedonian
and English 3%. There are only 2 records published in Russian and one in Albanian (Fig. 1).
700
600
500
400
300
200
100
0
577
non-conventional literature is usually available
from INIS, unless it is marked with the special indicator “X” (unavailable from INIS).
Journal articles represent about 50% of all
Macedonian input and papers from conferences
organized in our country 45%. Macedonian input
also includes doctor or master theses 5% and reports, basically scientific-technical projects financed by the Macedonian Ministry of Education
and Science (Fig. 2).
443
600
1
Al
b
R
us
2
495
500
462
400
300
M
ac
&E
ng
En
g
M
ac
27
200
0%
3
ok
s
Bo
is
R
ep
or
ts
Alb
es
Rus
55%
14
0
Th
Mac&Eng
42%
49
C
on
f. P
ro
c.
Eng
100
lls
Mac
0%
Jo
ur
na
3%
0%
5%1%
Fig. 1. Number of records (%) per language
Journals
Conf.Proc.
It can be concluded that almost half of the
documents are written in English, although Macedonia is a non-English speaking country. It reflects
the English oriented publishing policy of the domestic scientific journals. Excluding the journal
“Energetika” all Macedonian key journals for the
INIS Database (Fig. 3) are published mostly in
English.
2. Publication type
The INIS cataloguing rules specify different
types of records (i.e. book, journal article, report,
miscellaneous, patent, computer-medium, audiovisual material) and literary indicators (i.e. short
communication, conference, dictionary, numerical
data, legislative material, translation, thesis or dissertation, computer program description, standard
or specification, progress report, bibliography) that
indicate in which format the document reported to
the INIS Database is published. The full text of
49%
45%
Thesis
Reports
Books
Fig. 2. Number of records (%) per publication type
In order to help the user find journal titles
easily, INIS prepares the Authority List for Journal
Titles. This list is published annually and includes
the titles of all journals that have contained articles
submitted to the INIS Database. The statistical evidence of Macedonian journals regularly scanned
and key journals is shown in Fig. 3.
The journal “Energetika” has a high number
of records, since it is published quarterly. The rest
of the journals is published once or twice per year
(in some cases two numbers at once) depending on
available publishing resources of the respective
journal editors.
Mech. Eng. Sci. J., 26 (1), 33–37 (2007)
35
The role of the National INIS Center in presenting Macedonian nuclear and nuclear related sciences
Bulletin of the Chemists and Technologists of
Macedonia
29
Contributions-Macedonian Academy of Sciences and
Arts. Section of Biological and Medical Sciences
26
Contributions-Macedonian Academy of Sciences and
Arts. Section of Mathematics and Technical Sciences
13
258
Energetika
40
Geologica Macedonica
50
Physica Macedonica
Proceedings-Department of Mechanical Engineering,
University of Skopje
54
0
50
100
150
200
250
300
Fig. 3. Macedoniam journals
3. Subject categories
200
Ma{. in`. nau~. spis., 26 (1), 33‡37 (2007)
150
100
50
S7
5
S7
1
S6
2
S5
8
S4
3
S3
6
S2
2
S1
7
S1
3
S0
3
0
S0
1
INIS is a subject-oriented bibliographic database and according to its rules, the assignment of
the primary subject category to each INIS record is
mandatory. The primary category should be one
for which the scope description encompasses the
main INIS topic discussed in the piece of literature.
The subject categories are defined in the
ETDE/INIS subject classification scheme. In January 2000 the old subject categories was replaced by
a new simplified categorization scheme, containing
45 one-level broad subject categories from which
42 only are within the INIS subject scope. The new
categories have three-character alphanumeric
codes [Tab. 1].
In determining the main INIS areas of the
Macedonian input, the primary subject categories
are analyzed. In order to reach uniform and comprehensive analysis, the old category codes have
been converted to the new. It can be concluded that
the subject fields with the highest number of records are topics on energy sources (fossil and renewable), environmental sciences, materials science, engineering related to nuclear science and
technology. (Fig. 4)
Fig. 4. Records arranged by the primary subject category
Table 1
ETDE/INIS Subject Category Codes
S01
COAL, LIGNITE AND PEAT
S02
PETROLEUM
S03
NATURAL GAS
S04
OIL SHALES AND TAR SANDS
S07
ISOTOPES AND RADIATION SOURCES
S08
HYDROGEN
S09
BIOMASS FUELS
36
S10
`M. Sejmenova-Gichevska
SYNTHETIC FUELS
S11
NUCLEAR FUEL CYCLE AND FUEL MATERIALS
S12
MANAGEMENT OF RADIOACTIVE WASTES AND
NON-RADIOACTIVE WASTES FROM NUCLEAR
FACILITIES
S13
HYDROENERGY
S14
SOLAR ENERGY
S15
GEOTHERMAL ENERGY
S16
TIDAL AND WAVE POWER
S17
WIND ENERGY
S20
FOSSIL-FUELED POWER PLANTS
S21
SPECIFIC NUCLEAR REACTORS AND
ASSOCIATED PLANTS
S22
GENERAL STUDIES OF NUCLEAR REACTORS
S24
POWER TRANSMISSION AND DISTRIBUTION
S25
ENERGY STORAGE
S29
ENERGY PLANNING, POLICY AND ECONOMY
S30
DIRECT ENERGY CONVERSION
S32
ENERGY CONSERVATION, CONSUMPTION AND
UTILIZATION (ETDE only)
S33
ADVANCED PROPULSION SYSTEMS (ETDE only)
S36
MATERIALS SCIENCE
S37
INORGANIC, ORGANIC, PHYSICAL AND
ANALYTICAL CHEMISTRY
S38
RADIATION CHEMISTRY, RADIOCHEMISTRY
AND NUCLEAR CHEMISTRY
S42
ENGINEERING
S43
PARTICLE ACCELERATORS
S46
INSTRUMENTATION RELATED TO NUCLEAR
SCIENCE AND TECHNOLOGY
S47
OTHER INSTRUMENTATION (ETDE only)
S54
ENVIRONMENTAL SCIENCES
S58
GEOSCIENCES
S60
APPLIED LIFE SCIENCES
S61
RADIATION PROTECTION AND DOSIMETRY
S62
RADIOLOGY AND NUCLEAR MEDICINE
S63
RADIATION, THERMAL AND OTHER
ENVIRONMENTAL POLLUTANT EFFECTS ON
LIVING ORGANISMS AND BIOLOGICAL
MATERIALS
S70
PLASMA PHYSICS AND FUSION TECHNOLOGY
S71
CLASSICAL AND QUANTUM MECHANICS,
GENERAL PHYSICS
S72
PHYSICS OF ELEMENTARY PARTICLES AND
FIELDS
S73
NUCLEAR PHYSICS AND RADIATION PHYSICS
S74
ATOMIC AND MOLECULAR PHYSICS
S75
CONDENSED MATTER PHYSICS,
SUPERCONDUCTIVITY AND SUPERFLUIDITY
S98
NUCLEAR DISARMAMENT, SAFEGUARDS AND
PHYSICAL PROTECTION
S99
GENERAL AND MISCELLANEOUS
CONCLUSION
In accordance with the decentralized philosophy of the INIS System, INIS National centers collect nuclear related information published within
their boundaries, prepare the associated input and
send it to the INIS Secretariat at the IAEA in Vienna. The INIS Secretariat then provides quality
control of the input submitted by all INIS Members
and produces various formats of information products, available to the nuclear community in both
developing and developed countries. Macedonia
contributes to this system through its National
INIS Center, making the Macedonian nuclearrelated literature visible worldwide and facilitating
the transfer of nuclear knowledge among Macedonian scientists. The International Nuclear Information System (INIS) is an excellent mechanism of
international cooperation that brings benefit to all.
REFERENCES
[1] N. Marinkovic: Research Reactor Records in the INIS
Database – A Bibliometric Study, March 2002.
[2] W. Mandl: Impact and public acceptance of INIS’ bibliographic studies, April, 2002.
[3] C.-D. Hillebrand: Analysis of Low and Medium Physics
Records in Databases: Science and Technology Indicators in Low and Medium Energy Physics (with particular
emphasis on Nuclear Data), November, 1998.
[4] C.-D. Hillebrand: A Survey on Publications in Fusion
Research and Technology: Science and Technology Indicators in Fusion R & T, October, 1998.
[5] D. Dimitrov: Bibliometriska analiza na spisanieto “Bibliotekarska iskra”, Bibliotekarstvo, 23 (2), 19–28 (2005).
[6] Marija Sejmenova-Gichevska: The Republic of Macedonia in the International Nuclear Information System
(INIS), Bibliotekarska iskra, 17 (1–2), 99–104 (1999).
[7] Marija Sejmenova-Gichevska, Slave Jakimovski: The
Journal "Zbornik na trudovi – Mašinski fakultet Skopje"
in the International Nuclear Information System (INIS),
Zbornik na trudovi – Mašinski fakultet Skopje, 19 (1), 3–
10 (2000).
[8] Marija Sejmenova-Gichevska: The digital collection of
the INIS center for the Republic of Macedonia, Bibliotekarstvo, 22 (2), 77–81 (2004).
[9] Atieh Taghrid, Robert Workman: INIS: The World’s
Nuclear Knowledge Reservoir, IAEA Bulletin, 47 (1), 50–
51 (Sep 2005).
[10] ETDE/INIS-02: Subject Categories and Scope Description, IAEA, Vienna, 2002.
[11] IAEA-INIS-11 – INIS: Authority List for Journal Titles,
IAEA, Vienna, 2006.
[12] Presenting INIS, IAEA, Vienna, 1999.
Mech. Eng. Sci. J., 26 (1), 33–37 (2007)
The role of the National INIS Center in presenting Macedonian nuclear and nuclear related sciences
37
Rezime
ULOGATA NA NACIONALNIOT CENTAR NA INIS VO PREZENTACIJATA
NA MAKEDONSKITE NUKLEARNI I NUKLEARNO ORIENTIRANI NAUKI
Marija Sejmenova-Gi~evska
Nacionalna i univerzitetska biblioteka „Sv. Kliment Ohridski“,
MK-1000 Skopje, Republika Makedonija
[email protected]
Klu~ni zborovi: INIS; makedonski centar na INIS; baza na podatoci na INIS
Република Македонија е 95-та членка на INIS i нејзиното учество во овој децентрализиран систем започна
во 1996 година кога беше формиран Македонскиот центар
na INIS во рамките на НУБ „Климент Охридски“ – Скопје. Основната цел на оваа студија е да даде преглед на
македонските нуклеарни науки и нуклеарно ориентирани
Ma{. in`. nau~. spis., 26 (1), 33‡37 (2007)
науки дадени во базата на податоци na INIS. Презентирана е статистичка анализа на придонесот на Македонскиот
центар за базата на податоци на INIS од неговото формирање до 2006 година преку давање преглед на податоците
за јазиците, типот на публикациите и категориите според
INIS и нивните нумерички karakteristiki.

Mech-Eng-26-1-2007 - Mechanical Engineering Scientific Journal

Transcription

Similar documents

Qualitätsmanagement

Sluzben vesnik na RM, br.55, Petok, 20 juli 2001

GROÃZÃGIGE, REPRÃSENTATIVE, VIELSEITIG NUTZBARE

Programm Programme - International Nuclear Law Association

Montageanleitung Spezial-Versenkantenne AUTA 3100

haarschneider mit keramikklinge

New Chemical Branding at K.Walter

Seminarkatalog 2015/2016

Merkmale Features Riegelkurve EMT 15K Retiring Cam EMT 15K

Die Ethnophotographie in den von Rumänen Bewohnten Gebieten

Neues Seniorenwohnheim in Holzrahmenbauweise

Neues-von-NEC-Enterprice-Solutions

2 - IVECO

Cas Interface 3 Benutzerhandbuch

Ray Bradbury, There Will Come Soft Rains

direct - Wieland Dental

Handbuch "Clinical Trials"

SMR SP-ch:Layout 1

039078/06-05 PH570

Produktpass - PDF

Produktzertifizierung für den Zutritt zum Weltmarkt

Arheolo{ki institut Beograd Kwiga LXIV/2014.