Mean value
20.6x106 pSi
1.49x106 PSI
1.04x106 pSi
1.95x10-2
0.75x106 pSi
0. 15x10-4
Young's modulus along fiber direction
(El)
Young's modulus transverse to fiber
direction (E2)
In plan shear modulus (Gl2)
Minor Poisson ratio (1)
Transverse shear modulus (G23)
CTE across fiber direction (002)
Deterministic Design
The design problem is formulated as
approximation. The uncertainties in the material properties are represented by 11 random
variables, six for elastic properties (El, E2, G12, p, G23 and a2) and five for strength
allowables (ay cl 2t o, 2c" and ft"), which are assumed to be normally distributed and
uncorrelated. The mean values and coefficients of variation of the uncertainties in
material elastic properties and strength allowables are shown in Table 8-12 and Table 8-
13 respectively. The six design variables (b, h, tl, 62, t2 and 62) are aSSumed to be
uniformly distributed with percent variation given in Table 8-14. These data are intended
only for illustration.
Table 8-12. Uncertainties in material elastic properties (AS4) modeled as normal
distribution with coefficient of variation of 0.03
Table 8-13. Uncertainties in material strength properties (AS4) modeled as normal
distribution with coefficient of variation of 0.05
Mean value 331000 psi 208900 psi 8300 psi 33100 psi 10300 psi
Table 8-14. Variation of the random design variables around nominal design value
b h tl Bi t2 2i
Variation fl% f2% f4% f10 f4% f10