Abstract: An all hexahedral finite element mesh (FEM) generation method is proposed for complex mechanical structure, with the purpose to guarantee finite element simulation efficiency and precision in complex mechanical structure. The error characteristics and its cause in focus local mesh are analyzed by the finite element mesh error estimation. Based on the geometrical features and physical properties of the complex mechanical structure, the recognition criteria of critical region are established. Hexahedral mesh generation algorithm and implementation steps are presented based on the virtual planning model of structure calculation domain and the mesh quality evaluation criterion is also build. Numerical examples show that this method has the ability to generate all hexahedral finite element mesh for complex mechanical structure and critical regions are expressed accurately, and global mesh is distribution with rationality and high quality.

Key words: complex mechanical structure;hexahedral-mesh;critical region;virtual planning model