A METHOD FOR SOLVING THE STRUCTURAL INTERVAL FINITE ELEMENT EQUATIONS

A simple method for solving structure static interval element equations which were established by the interval finite element method was presented. In this method, the global stiffness matrix was expanded at first order on the middle value of interval variables by Taylor series. After the expansion expression of stiffness matrix was dealt approximately, the inverse matrix of an uncertain stiffness matrix was expressed as a series of Neumann expansion series. The full use of the sub-distribution law and other arithmetic rules of interval analyses were made to reduce the extension caused by interval analyses. Finally, the computational formulas of the upper and lower boundaries of the uncertain structure responses were developed. The calculated results of several numerical examples show that the proposed method has good accuracy and is feasible and effective, and easy to implement.