from and driven by the design optimization to improve the efficiency of RBDO. If n
iterations are needed for convergence, the approach needs n deterministic optimizations
and n probabilistic analyses. However, the convergence rate of subsequent probabilistic
analyses is expected to increase after obtaining a reasonable MPP. Wu et al. (2001)
demonstrated the efficiency of this approach by optimizing a beam subject to multiple
reliability constraints.
Deterministic Design
Optimization
Probabilistic Analyses:
FORM/SORM Probabilistic analyses to
replace random variable
with deterministic values
Safety factor based x* x*
Deterministic Design
Otimization with x* j Deterministic design
optimization with x*
New design d
No ign and Reii
Yes
Stop
Figure 2-3. Partial safety factor approach: decouple reliability analysis and design
optimization
Summary
Since the reliability analyses involved in our study are for system probability of
failure, MCS was used to perform reliability analysis. We developed an analysis RS
approach to reduce the high computational cost of MCS and design response surface
approach to filter noise in RBDO (Chapter 3).