Reliability‐Based Vector Optimization of Structural Systems

Abstract

Virtually all structural optimizations based on system reliability were conducted considering only the ultimate state of plastic collapse initiated from the intact (i.e., undamaged) system. These single‐objective optimizations may result in decreasing the safety levels with respect to other limit states of concern, such as deformation, plastic hinge occurrences, and residual system reliability. Motivated by the need of a rational reliability‐based multilimit‐state optimization approach, where different conflicting requirements in the design of structural systems are considered simultaneously, a vector‐optimization approach is formulated. In this approach a vector‐valued objective function is examined, and the system safety is considered with regard to multiple reliability requirements imposed simultaneously. The solution to this problem is defined as the set of noninferior solutions in the space of decision variables. A three‐step reliability‐based vector‐optimization searching strategy is suggested, a decision support space is proposed, and examples of solutions for both nondeterministic truss and frame systems are presented.