OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
nature of the SD (Standard deviation) variation is linear and passing through the origin. Hence, the presented results
would be sufficient to extrapolate the results for other SD/mean value keeping in mind the limitation of FOPT Liu et
al.(1996). The basic random variables such as E 1 , E 2 , G 12 , G 13 , G 23 , υ 12 , α 1 , α 2 are sequenced and defined as appendix.
b= E, b = E , b = G, b = G, b = G, b = ν , b = α, b = α,
b = h
1 11 2 22 3 12 4 13 5 23 6 12 7 1 8 2 9
The following material properties are used for computation:
d
11
40 d 22, d d 12 13
0.6 d 22, d 23
0.5 d 22, d
d -6 0 -1 d -6 0 -1 d -6 0 -1 d
9
E = E G = G = E G = E ν12
= 0.25, ρ = 1. αl = 1.14*10 C , αt = 11.4*10 C , α0 = 1*10 C , E22
= 6.92*10 Pa .
In the present study various combination of edge support conditions namely clamped (C) and simply supported (S)
have been used for the investigation. The boundary conditions for the plate are as:
All edges simply supported (SSSS):
v= w= θ = ψ = 0, at x= 0, a; u = w= θ = ψ = 0at y = 0, bAll edges clamped (CCCC):
y y x x
u = v = w = ψ = ψ = θ = θ = 0, at x = 0, a and y = 0, b;
x y x y
Two opposite edges clamped and other two simply supported (CSCS):
u = v = w = ψ = ψ = θ = θ = 0, at x = 0 and y = 0; v = w = θ = ψ = 0, at x = a u = w = θ = ψ = 0, at y = b
x y x y
y y x x
4.1 Comparison results: mean and second-order statistics
In order to verify the accuracy of the present finite element formulation in dimensionless nonlinear thermal buckling
analysis of laminated composite angle-ply [0 0 /45 0 /45 0 /0 0 ] square plate with various aspect ratios and with uniform
thermal loading condition having all edges simply supported is shown in Table 2(a) and 2(b), and compared with the
results obtained by Liu and Huang (1996). Clearly, it is seen that the present finite element results obtained by HSDT
are in good agreement with that obtained by Liu and Huang analysis using the first-order shear deformation plate
theory. The maximum difference is about 2%.
Due to unavailability of results concerning the buckling of composite plates subjected to thermal loading with
randomness in system properties, the existing result concerning the random linear buckling of laminated composite
plates in thermal environment has been validated by comparing the results obtained from present DISFEM approach
with an independent MCS approach with various buckling load. It is assumed that one of the material property (i.e.,
E 11 ) change at a time keeping other as a deterministic, with their mean values of the material properties. For the MCS
approach, the samples are generated using Mat Lab to fit the desired mean and SD.
Table 2(a), 2(b) examines the effect of temperature distribution variations (uniform, linearly, tent like and parabolic)
with fiber volume fraction (Vf=0.6) and temperature changes (∆T=100C°, 0°C ) for random change in all material
properties (bi) on the dimensionless
Mean and coefficient of variation of buckling load on laminated composite plates having simply supported boundary
conditions with temperature independent (TID) material properties. It can be observed that for the same fiber volume
fraction and temperature change, the dimensionless mean buckling load of the plate is highest when plate has uniform
constant temperature variation. It is noted that the coefficient of variation of buckling load is almost same for the
plates subjected to uniform constant, linearly and tent like temperature variations but coefficient of variation of
buckling load on plate subjected to parabolic temperature distribution is highest
5. CONCLUSION
Table 1(a) Comparisons of buckling loads Px (KN) for perfect (±45 0 )2T laminated square plates (a/h=10) under sets
of environmental conditions
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