deterministic optimization. The approximation domain of design response surface
approximation and thus the search domain of the optimization is rather limited compared
to the whole design space. In order to fully explore the potential of reliability-based
design optimization, RBDO and design response surface construction must be performed
repeatedly to cover the entire design space, which is computationally prohibitive. To
address this problem, RBDO is converted to equivalent deterministic optimization in
order to reduce the computational cost and explore the entire design space as shown in
Chapter 7.
Reliability-Based Design Optimization Using Sequential Deterministic Optimization
with Probabilistic Sufficiency Factor
For the deterministic design, where the deterministic safety factors are given in
Table 8-15, reliability analysis using Monte Carlo simulation shows the critical failure
mode is the strength failure model and the probabilistic sufficiency factor. The deficiency
in safety factor of strength failure mode can be corrected by using the probabilistic
sufficiency factor, which is the factor to be applied to the response to meet the target
probability of failure requirement.
In the next design iteration, the safety factors of those failure modes that are not
active in the last design iteration remains the same. The safety factor of the critical failure
modes are chosen to be
(k+1) S(k
s > '(8-3)
P i(k)
which are used to reduce the allowables a, for the corresponding failure modes.
Since PANDA2 approximates the safety margins in optimization and it usually
errors on the conservative side in approximation, the actual safety margins from