A mechanism reliability analysis method based on polynomial chaos expansion

Mechanism reliability analysis method is proposed based on polynomial chaos expansion, which is adopted to approximate to the limit function in this paper. The computational efficiency of reliability analysis is improved while achieving the same accuracy level. Firstly, uncertainty input variables are transformed into standard Gaussian distribution variables and the limit function is expressed as polynomial chaos expansion using Hermite polynomial bases. Thus the complexity of polynomial chaos expansion is greatly simplified with orthogonal characteristics between Hermite polynomial and standard Gaussian distribution probability density function. Then, the Probability Collocation method is adopted to determine the coefficient of polynomial chaos expansion and achieve complete polynomial chaos expansion. On this basis, the random simulation method is used to compute the mechanism reliability. Finally, reliability analysis is carried out with this method to a four-link mechanism. After the contrast with Monte Carlo method, the results indicate that polynomial chaos expansion improves the computational efficiency while achieving the same accuracy level.