MODELING OF MATERIAL UNCERTAINTIES USING THE NONLINEAR STOCHASTIC FINITE ELEMENT METHOD

摘要

The modeling of material uncertainties in terms of the method to be used for probabilistic analysis and the stochastic description of material properties are discussed. Using FORM, a nonlinear stochastic finite element method is proposed by tracking the stochastic variation of the response at every step of a deterministic analysis. In the context of SFEM, the random material properties are represented by continuous and discontinous random fields. Commonly used methods are discussed. To implement the alogorithm economically and efficiently, the concept of sensitivity index is introduced. The selection of the optimal random field element mesh size is briefly discussed. With the help of a small example, it is shown that the consideration of nonlinear material behavior and the uncertainty associated with it are essential in the estimation of the reliability of a structural system. The stochastic finite element algorithm proposed here can be used for this purpose.