奚金荣^*， 尹小刚

（  河海大学工程力学系；  ）

摘要： 局部非协调网格引入约束方程的方法一般有两种，一是罚函数法，只能保证约束方程近似满足；二是直接引入法，能保证约束方程精确满足。本文简单介绍几何协调和运动协调的概念。在考虑位移模式协调性的前提下，给出一种等参逆变换方法，并在此基础上生成约束方程，且对约束方程法进行了改进。在保证几何协调的基础上，从整体劲度矩阵层面，运用大数法处理网格非协调问题，从而保证了整体劲度矩阵的对称性，实现了局部非协调网格位移的协调性。以空间八节点等参元为例给出推导公式，经过举例验证，此方法在保持计算精度的前提下，可简化网格划分，大大减少计算量，具有合理性和可行性。
关键词： 等参逆变换；几何协调；运动协调；大数法；非协调网格

Xi Jinrong^*， Yin Xiaogang

（  Department of Engineering Mechanics, Hohai University；  ）

Abstract： There are two general ways to introduce local non-conforming grid into constraint equation: penalty function method which can only be bound to guarantee the constraint equation to meet requirements approximately, direct introduction method which can be bound to guarantee the constraint equation to meet requirements precisely. In this paper, a brief introduction has been taken on the concept of geometry coordination and movement coordination. Under considering the co-ordination of the displacement mode, an isoparametric inverse transform method has been given. On the basis, constraint equations generate and have been improved. On the basis of ensuring the geometry coordination and on the overall stiffness matrix level, the large number method has been taken to deal with non-coordination of the grid to ensure the symmetry of the overall stiffness matrix and achieve the displacement coordination of local non-conforming grid. Derived formula has been given combining with space eight-node isoparametric elements. The verification shows that the method can simplify the grid and reduce the calculation amount greatly under maintaining the accuracy and it is reasonable and feasible in practical projects.

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