The current RBDO frameworks mostly deal with the probability of failure of
individual failure modes, an efficient framework must be developed to address RBDO for
the system probability of failure. Chapter 6 developed an inverse reliability measure, the
probabilistic sufficiency factor, to improve the computational efficiency of RBDO, to
design for low probability of failure, and to estimate the additional resources needed to
satisfy the reliability requirement. Chapter 7 demonstrated the use of probabilistic
sufficiency factor with multi-Hidelity techniques for RBDO and converting RBDO to
sequential deterministic optimization. The methodology is applied to the RBDO of
stiffened panels in chapter 8.