摘要：Using random variables to describe uncertain parameters in structural systems, its initial strength and the evolution pro?cess of the strength degradation is regarded as the Gamma process. In this article, we propose a new method on reliabil?ity sensitivity numerical analysis of mechanical structure based on Gamma processes. Then, we use the fourth moment method based on frequency curve of Pearson to solve the problem of reliability calculation with random parameters of arbitrary distributions. Formulas for calculating the reliability sensitivity with respect to the mean and the variance of the random variables are derived. The reliability analysis of the welded box girders of crane is taken as an example to verify the proposed method. The results show that the method can effectively solve the problem of the reliability sensitivity of structural systems with strength degradation.
关键词：Sensitivity analyses; strength of welded structures; strength degradation; moment method; frequency curve of Pearson
