Decoupled and Single Loop Methods for Reliability-Based Optimization and Robust Design

Several procedures have been developed in the literature for reliability-based design optimization (RBDO), including the Reliability Index Approach (RIA), the Performance Measure Approach (PMA), and more recent techniques wherein the reliability and optimization calculations are decoupled. This paper extends the decoupled approach to include standard deviations as design parameters and wherein simulation or other methods can replace the traditional first order analytical method for reliability assessment. The methods are extended to robust design and their applicability is investigated. The paper also investigates a single loop method and extends it for the robust design problem. The accuracy and computational efficiency of the various RBDO methods are compared.