有限元计算中疏密网格间过渡单元的构造

连接密网格与疏网格的过渡单元对有限元计算结果的精度有较大的影响。为了提高有限元计算的精度，对于等参实体单元的网格中变节点数过渡单元，提出了本质上相同的两种修正方法——修改插值函数法和引入虚拟节点法。实现了过渡单元与所连接单元间位移的协调性，并保证了它们之间刚度的匹配性，从而使之能够满足有限元收剑准则。所提出的方法在数值实现上简单易行。计算结果与解析解一致，与ＡＤＩＮＡ法相比，精度有很大的提高。

Construction of the transition elements between the sparse and dense meshes in the finite element computation

In the mesh generation of the finite element computation, the transition elements connecting the dense and sparse meshes have great effect on the precision of the computational results. To improve the precision of finite element analysis, considering the transition elements with varying nodes in the mesh of the isoparameter elements, this paper suggested two modified methods with the same essentiality the modified interpolated function method and introducing virtual nodes method, and realized the displacement compatibility between the transition elements and the connected elements. The matching of the stiffness between them was also guaranteed so that the convergence condition was satisfied. The suggested methods are simple and easy to practice numerically. Compared with ADINA program, the results of the computation show the methods has a great improvement.