further. Table 5-12 shows that this conclusion applies also to the elastic moduli,

coefficients of thermal expansion, and stress-free temperature. By comparing with Table

5-10, we see that truncating any of the other parameters at -2 o does not change the

failure probability as significantly as truncating 82u at -4 o. Note that some probabilities

from truncated distributions are slightly larger than those from untruncated distributions,

which is due to the sampling errors.

 Table 5-11i. Effects of quality control of st", sil, E21, and Y12 On probability of failure of
 0.12 inch-thick (f6)s laminates
 Probability of failure from MCS 10,000,000 samples

 Un-truncated Truncated Truncated Truncated Truncated
 Normal e1U at -20 s/1 at -20 eat at -20 77, at -20

 24.00 60.5e-6 58.6e-6 61.5e-6 54.4e-6 55.4e-6

 25.00 56.5e-6 53.0e-6 52.3e-6 54.0e-6 53.2e-6

 26.00 60.7e-6 63.4e-6 62.0e-6 60.1e-6 61.0e-6


Table 5-12. Effects of quality control of El, E2, G12, Cl12, Tzero, al, and a2 On probability
 of failure of 0. 12 inch-thick (f6)s laminates
 Probability of failure from MCS 10,000,000 samples by truncating
 B at -20
 E1 Ez Gol go1 Tzero ao at

 24.00 62.2e-6 52. 1e-6 57.8e-6 51.8e-6 54.6e-6 52.7e-6 58.2e-6

 25.00 52.5e-6 48. 1e-6 55.1e-6 49.7e-6 55.1e-6 56.8e-6 54.4e-6

 26.00 54.5e-6 59. 1e-6 60.4e-6 59.4e-6 59.8e-6 63.0e-6 60.4e-6



Effects of Quality Control on Optimal Laminate Thickness

 Quality control (QC) can be used to reduce the laminate thickness instead of the

probability of failure. Table 5-13 shows that QC of EZu at -30 will allow 0.1 inch-thick

laminates with failure probability below the required 0.0001.