NASA Technical Memorandum 106302 / .\ Buckling Analysis of Laminated Thin Shells in a Hot Environment Pascal K. Gotsis and James D. Guptil Lewis Research Center Cleveland, Ohio September 1993 I IASA (NASA-TM-106302) BUCKLING ANALYSIS UF LAMINATED THIN SHELLS IN A HOT ENVIRONMENT (NASA) 22 p G3/39 N94-14776 Unclas 0189396
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NASA Technical Memorandum 106302 /
.\
Buckling Analysis of Laminated ThinShells in a Hot Environment
Pascal K. Gotsis and James D. GuptilLewis Research Center
Cleveland, Ohio
September 1993
I IASA
(NASA-TM-106302) BUCKLING ANALYSIS
UF LAMINATED THIN SHELLS IN A HOT
ENVIRONMENT (NASA) 22 p
G3/39
N94-14776
Unclas
0189396
BUCKLING ANALYSIS OF LAMINATED THIN SHELLS IN A HOT ENVIRONMENTI
Glass transition temperature, °C ........... 215.55
14
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I Vibration AnaJyzer _/_
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I ElectromagneticAnalyzer (EMAN) I
I Executivemodule
,,_ Dedicated data base I
INonlinear solvers Iand history tracking
_X_ Utility routines I
VideosGra )hs
Figure 1.-.-CSTEM modular structure.
To globalstructural
analysis /
//
// Laminate
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From global
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1 analysis
_'_'-"-'_ _ I_r Laminate \
& Laminate _ _ Laminate J \ __
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Constituents Materials properties J
P= f(T, M, t) jJ
Figure 2.--Integrated Composite Analyzer (ICAN).
15
A: Matrix
B: Matdx and fiber
31 /-- MatrixI
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Regions of
constituent
mated=is
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__f - T ''2PMO kTGo-ToJ
TGW = (0.005M2-0.1M+ 1)TGD
PM matrix property at current temperature T
PMO matrix property at reference temperature TO
TGW wet glass transition temperature
TGD dry glass transition temperature
M moisture
Figure 3.--Regions of constituent materials andnonlinear material characterization model.
• S
(a) Geometry:/JR = 4; RIt = 33.3; R = 25.4 cm.
///// J
I//////_l\\\\\\t._
Angle-ply laminate [6/-8]2
(I0) Materials: fiber volume ratio = 55%; moisture = 2%;
T300 fibers; IMHS matrix.
Figure 4.--Geometry and materials of laminated thin
shells.
oo
T0
T_
n
:E
Processing I
I (-_,_ _-_._ _ :y[61-612 angk_-ply
___ .--- laminate
=,,=_
I v
(a) Thermal load Tg = 215.5 °C.
I
Time
i Buckling _XJ/
r
Time
(b) Axial compressive load S.
Figure 5._Load history.
_t
I_lllll"ll_nltlLnil I
@Figure 6.mThree-dimensional finite element mesh and
transverse croc,s-sectional area of laminated thin
shell_
16
[01-812angle-plylaminate
1"OF r'_ r-_ UR = 6
.8
.2
00 15 30 45 60 75 90
Ply angle, deg
Figure 7._lnfiuence of length ratio UR on bucklingbehavior of laminated thin shells. R/t = 33.3;
FVR = 55%; T = Tg/2; moisture = 2%.
9O
r===_
m
(t/4, t/4, t14, t14) and (t12, t/2)Uniform temperature and linear temperatureLong and short cylinders65% and 55% f'd_ervolume fractionsInternal pressure S/P = 100 and axial load SThin and thick cylinders[0/-6]2 and [0]4
75
60'E
=o
45c
P¢,
r',,3O
15
00 15 30 45 60 75 90
Ply angle, deg
Figure 8._Percent difference comparison of buckling load for different parameters.
17
[6/-8]2 angle-ply
laminate
I:_ PJt = 100
K_= R/t = 33.33
l PJt = 20
0 15 30 45 60 75 90
Ply angle, deg
Figure 9.---Influence of thickness ratio lilt on bucklingbehavior of laminated thin shell. L/R = 4;
FVR = 55%; T = Tg/2; moisture = 2%.
_ (u_ t/2),i [e,-0]i m (3t/8, t/8, t18, 3t/8),
[01-612 angle-ply [91-012
laminate m (t/4, t/4, t/4, t./4),
1"0 F _ [01-012
81
i.6 :
_ .4 .
i.z
0 15 30 45 60 75 90
Ply angle, deg
Figure 10.--Influence of ply thickness on bucklingbehavior of laminated thin shells. UR = 4;
R/t = 33.3; FVR = 55%; T= Tg/2; moisture = 2%;
B S/P = 140
l S/P= 120 [0/-0]2 angle-ply=
1.0
e_
z
00 15 30 45 60 75 90
Ply angle, deg
Figure 11 ._lnfluence of internal hydrostatic pressure
on buckling behavior of laminated thin shells.
/JR = 4; R/t = 33.3; FVR = 55%; T = Tg/2;
moisture = 2%.
]8
r--1 Uniformtemperature
Im Linear [el-O]2 angle-ply
temperature laminate1.0
--i ,8
.6
.4
.2
z
00 15 3O 45 60 75 90
Ply angle, deg
Figure 12.---Influence of temperature profile on buck°
ling behavior of laminated thin shells. UR = 4;
RIt = 33.3; FVR = 55%; moisture = 2%.
"o 1.0_°_ .8e-
E .2£.
0
[e]4BB [0/-612 or
[0/-eL,
0 15 30 45 60 75 90
Ply angle, deg
Figure 13.--Influence of layup configuration on buck-
ling behavior of laminated thin shells. L/R = 4;
R/t = 33.3; FVR = 55%; T = Tg/2; moisture = 2%.
FVR= 55%r-1
E WR = 60% [01-612 angle-ply
Ill FVR = 65% laminate
1.0
t,-
00 15 30 45 60 75 90
Ply angle, deg
Figure 14._lnfluence of fiber volume fraction (FVR) on
buckling behavior of laminated thin shells./JR = 4;
R/t = 33.3; T = Tg/2; moisture = 2%.
19
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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED
September 1993 Technical Memorandum5. FUNDING NUMBERS4. TITLE AND SUBTITLE
Buckling Analysis of Laminated Thin Shells in a Hot Environment
6. AUTHOR(S)
Pascal K. Gotsis and James D. Guptil
7. PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES)
National Aeronautics and Space AdministrationLewis Research CenterCleveland, Ohio 44135-3191
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESSEES)
National Aeronautics and Space AdministrationWashington, D.C. 20546-0001
WU-537-04-20
8. PERFORNNG ORGANBATIONREPORT NUMBER
E-8043
10. SPONSORING/MONffORINGAGENCY REPORT NUMBER
NASA TM- 106302
11. SUPPLEMENTARYNOTES
Responsible person, Pascal K. Gotsis, (216) 433-3331.
12a. DISTRIBUTION/AVAILABILITY STATEMENT
Unclassified - Unlimited
Subject Category 39
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum200 words)
Results are presented of parametric studies to assess the effects of various parameters on the buckling behavior ofangle-ply, laminated thin shells in a hot environment. These results were obtained by using a three-dimensional finiteelement analysis. An angle-ply, laminated thin shell with fiber orientation of [0/-0] 2 was subjected to compressivemechanical loads. The laminated thin shell had a cylindrical geometry. The laminate contained T300 graphite fibersembedded in an intermediate-modulus, high-strength (IMHS) matrix. The fiber volume fraction was 55 percent and
the moisture content was 2 percent. The residual stresses induced into the laminate structure during the curing weretaken into account. Parametric studies were performed to examine the effect on the critical buckling load of thefollowing parameters: cylinder length and thickness, internal hydrostatic pressure, different ply thicknesses, differenttemperature prof'des through the thickness of the structure, and different layup configurations and fiber volumefractions. In conjunction with these parameters the ply orientation was varied from 0° to 90 °. Seven ply angles wereexamined: 0°, 15°, 30°, 45 °, 60°, 75°, and 90°. The results show that the ply angle 0 and the laminate thickness had
significant effects on the critical buckling load. The fiber volume fraction, the fiber orientations, and the internalhydrostatic pressure had important effects on the critical buckling load. The cylinder length had a moderate influenceon the buckling load. The thin shell with [0/-0] 2 or [0/-0] s angle-ply laminate had better buckling-load performancethan the thin shell with [0]4 angle-ply laminate. The temperature profiles through the laminate thickness and variouslaminates with the different ply thicknesses has insignificant effects on the buckling behavior of the thin shells.