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针对目前弹性地基中的动力无限元由于含有频率项而无法在时域中计算的情况,本文构造了一种新型三维规则网格无限元,该新型无限元能够很方便地将无限元单元质量、刚度矩阵中含有频率的项转化为高阶动力方程中的项,从而形成高阶动力平衡方程;在参考二阶动力方程wilson-θ时域解法下,推导了一种新的高阶动力方程时域数值计算公式,从而实现有限元和无限元耦合法的时域计算.最后通过典型的波动问题算例来考察新型无限元的精度及有效性,结果表明,新的动力无限元具有较高精度.
In view of the fact that the dynamic finite element in the elastic foundation can not be calculated in the time domain because of containing the frequency term, a new three-dimensional regular grid finite element method is constructed in this paper. The new infinite element can easily integrate the element quality, The term containing the frequency in the stiffness matrix is transformed into terms in the higher-order dynamic equation to form a higher-order dynamic equilibrium equation. A new higher-order dynamic equation is derived by reference to the wilson-θ time-domain method Domain numerical calculation formula, so as to realize the time-domain calculation of finite element and infinite element coupling method.Finally, through the typical example of wave problem, the accuracy and validity of the new type of infinite element are investigated. The results show that the new dynamic element has higher accuracy .