Multitangent-plane surface method for reliability calculation

In this paper, a multitangent-plane surface method is suggested for calculating the reliability of complex structures of which the limit-state surfaces are not known explicitly. In this approach, multiple tangent planes are used to approximate the actual limit-state surface. Also radial importance sampling is used in conjunction with probabilistic finite-element (PFE) analysis. Numerical results suggest that the new method can be used to improve the accuracy of solutions obtained from first-order second moment (FOSM) analysis and also require considerably less CPU time when compared with Monte Carlo simulation (MCS) analysis. This method is only suitable for the case of a nonlinear concave or convex limit-state surface.