Fast method for computing failure probability of structural system

To find the failure probability for time independent structural system, which is expressed as multi-dimensional integration form, the method proposed by Melchers based on Monte-Carlo method is available, but it can give sometimes unreasoning results, because some subjective criteria may effect the important sampling function in use and no satisfactory subjective criterion can be found. The new fast simulation method, based on probability formula of sum of random events, was presented. Several importance sampling functions are separately used in turn and no subjective criterion is necessary. The calculated examples were given. The results have shown that calculated effectiveness is the same as Melchers method and the method is available for the case of linear of nonlinear safety margin function.