A NEW LOOK AT THE RESPONSE-SURFACE APPROACH FOR RELIABILITY-ANALYSIS

Closed-form mechanical models to predict the behaviour of complex stru ctural systems often are unavailable. Although reliability analysis of such systems can be carried out by Monte Carlo simulations, the large number of structural analyses required results in prohibitively high computational costs. By using polynomial approximations of actual limi t states in the reliability analysis, the number of analyses required can be minimized. Such approximations are referred to as Response Surf aces. This paper briefly describes the response surface methodology an d critically evaluates existing approaches for choosing the experiment al points at which the structural analyses must be performed. Methods are investigated to incorporate information on probability distributio ns of random variables in selecting the experimental points and to ens ure that the response surface fits the actual limit state in the regio n of maximum likelihood. A criterion for reduction in the number of ex periments after the first iteration is suggested. Two numerical exampl es show the application of the approach.