Reliability-based structural optimization using improved two-point adaptive nonlinear approximations

The objective of this paper is to conduct reliability-based structural optimization in a multidisciplinary environment. An efficient reliability analysis is developed by approximating the limit-state functions using two-point adaptive nonlinear approximation. The nonlinear approximation is constructed by using the function values and the first-order gradients at two points of the limit-state function, and its nonlinearity index is automatically changed for different problems. The reduction in computational cost realized in safety index calculation and optimization are demonstrated through two structural problems. This paper presents the safety index computation, analytical sensitivity analysis of the reliability constraints and optimization using frame and turbine blade examples. (C) 1998 Elsevier Science B.V. All rights reserved.