A Reliability-Based Optimal Design Using Advanced First Order Second Moment Method

Reliability-based optimization that is found in most literature has been formulated using the first order second moment (FOSM) method, because of its simplicity. In this paper, an advanced FOSM method is adopted, in order to better approximate probabilities. The resulting formulation becomes a modified parametric optimal design problem and a parametric optimal design technique is utilized to solve it. The finite element method is incorporated with the formulation and a detailed sensitivity analysis is made. In order to illustrate application of the present methodology, several numerical calculations are carried out for a three-bar truss and a twenty five-bar truss structure under several load conditions. In these examples, loads and yield stress are taken as random parameters with normal distribution.