Table 8-19. Design history of RBDO based on sequential deterministic optimization
 using probabilistic sufficiency factor to correct safety factor directly by
 Equation (8-3)
Safety Minimize obj ective function W while pof <0. 0001
factor for Obj ective PoflPSF from Critical strength
strength [b, h, t,, 81, tz, 82] function: MCS of 106 failure mode
failure mode weight (lb) samples* (load case 1)
Initial [9.999, 1.583,.
design 0.02229, 87.57, 3386 .008978/0.837178 Iordi-ln
 3 shear
 (s =1.2) 0.0395, 14.84]
 S = [9.997, 0.9701,
 Skin transverse-
s /0.837178 0.01828, 89.54, 3192 0.00000/1.179381
=1.437514 0.07011, 0.1484] esl
S3 [9.997, 0.8254,
 Skin transverse-
s2/1.179381 0.005205, 90.00, 1878 0.001875/0.944237
 tensile
=1.218872 0.07087, 0.9826]
 pof = probability of failure, PSF = probabilistic sufficiency factor

 Table 8-20. Design history of RBDO based on sequential deterministic optimization
 using probabilistic sufficiency factor to correct safety factor by actual safety
 margin using Equation (8-4)
Safety Minimize obj ective function W while pof <0. 0001
factor for Obj ective PoflPSF from Critical strength
strength [b, h, t,, 81, tz, 87] function: MCS of 106 failure mode
failure mode weight (lb) samples (load case 1)
Initial [9.999, 1.583,.
 Isogrid in-plane
design 0.02229, 87.57, 3386 0.008978/0.837178
(s =1.2) 0.0395, 14.84]~ ha
S2= [9.997, 0.9701,
 Skin transverse-
s /0.837178 0.01828, 89.54, 3192 0.00000/1.179381
=1.437514 0.07011, 0.1484] esl
S3= [9.997, 1.137,
 s2/1.7938lSkin transverse-
 s21.79810.006349, 90.00, 2058 0.000080/1.002482
 tensile
=1.218872 0.05445, 0.001495]
 pof = probability of failure, PSF = probabilistic sufficiency factor

 It is seen that the third designs in Table 8-19 and quite different from that in Table

 8-20, because the different correction formulation used. The designs in Table 8-19 use

 direct correction to the safety factors employed in the previous design iteration shown by

 Equation (8-3), while designs in Table 8-20 employed correction to the actual safety

 margins of the previous design iteration shown by Equation (8-4). Comparing the third