结构区间有限元方程组的一种解法

A METHOD FOR SOLVING THE STRUCTURAL INTERVAL FINITE ELEMENT EQUATIONS

  • 摘要: 针对结构静力区间有限元方程组的求解提出了一种简易解法。该法将含区间变量的整体刚度矩阵在区间变量的中值处进行一阶泰勒式展开。在对刚度矩阵展开式进行近似处理之后,将刚度矩阵的逆矩阵用一系列的Neumann展开级数来表示。为减小区间运算的扩张,利用区间乘法运算的次分配律和相关运算规则,导出不确定结构响应量上界、下界的计算式。几个算例结果分析表明:该方法具有较好的精度,是可行和有效的,且易于编程实施。

     

    Abstract: 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.

     

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