An Optimum Design Method Based on Structural Systems Reliability

Abstract

This study deals with the methodology of structural design with a constraint on system reliability. A structure with high redundancy usually possesses a number of failure modes, which results in difficulty in evaluation of system reliability. Two optimum design problems are formulated with reliability constraints on elements and failure modes, respectively. The constraint on system reliability is not directly introduced into the design space, but it is satisfied through control of the constraints on element reliabilities or on the formation probabilities of failure modes in optimization. Sensitivity analysis on element reliabilities is performed to reduce the computation effort in the design process. It is shown from numerical results that the proposed method is effective for designing structures at specified system reliability levels.