Two-Level Approximation Method for Reliability-Based Design Optimization

In order to model uncertainties and achieve the required reliability, Reliability Based Design Optimization (RBDO) has evolved as a dominant design tool. Many methods have been introduced in solving the RBDO problem. However, the computational expense associated with the probabilistic constraint evaluation still limits the applicability of the RBDO to practical engineering problems. In this paper, a Two-Level Approximation method (TLA) is proposed. At the first level, a reduced second order approximation is used for better optimization solution; at the second level a linear approximation is used for faster reliability assessment. The optimal solution is obtained interatively. The proposed method is tested on certain numerical examples, and results obtained are compared to evaluate the cost-effectiveness.Copyright © 2004 by ASME