An Approach Of Nonlinear Reliability Analysis Based On Single Failure Mode

Since the birth of reliability design in 1960s,reliability plays a very important role.And the reliability calculation immediately becomes a focus of research by most scholars.what's more,its has been made great progress in theory and applications.When the random variables for the linear explicit, they can calculate the precise reliability.But for the nonlinear variables,a lot of bias exist on the calculation of reliability with AFSOM method.Nowadays the main method of calculating the reliability coefficient for nonlinear failure mode is the optimization method, that is,optimizing the shortest distance between the limit state equation of surface and coordinate origin. Should be said that the optimization method used for reliability analysis is very effective,but the existing methods are too complex to compute, and sometimes necessary to compute the second-order partial derivatives or the inverse matrix,so it is difficult to put them into practice.In this paper,it gives an approach method to nonlinear reliability analysis.First,the paper defines two types of regional:the gibbous safety region and the gibbous failure region.Second,it is detailed description of how to obtain the approaching mode and to set up computing mode of correlation linear system reliability.And the nonlinear reliability is transformed to correlation linear system reliability.Third, tow methods of linear regression algorithms and numerical analysis and fitting algorithm are found out from the many system reliability calculations.Last,The examples are given to compare different methods of the computed results.From the results of analysis,different algorithm for different failure modes,and it shows the approximate calculation with the calculation easy and high precision characteristics.Studies have shown that the methodology in this paper is feasible,it can lay a solid foundation for the more complex nonlinear model of reliability calculation.