Polyhedral elements with strain smoothing for coupling hexahedral meshes at arbitrary nonmatching interfaces

Managing nonmatching interfaces between dissimilar hexahedral meshes is complicated because the interfaces, which are arbitrarily formed by the intersection of element-edges, are composed of various types of polygons. In this paper, a simple and efficient scheme is proposed for dealing with nonmatching interfaces using polyhedral elements. Because polyhedral elements can have arbitrary numbers of polygonal faces and nodes, they can be used as transition elements for coupling nonmatching meshes. A strain smoothing technique in the cell-based smoothed finite element method is introduced to resolve critical difficulties in defining shape functions and in conducting numerical integration for the polyhedral elements, as well as to further enhance the accuracy and efficiency of finite element analyses. The effectiveness of the proposed scheme is demonstrated through several numerical examples involving nonmatching interfaces. The effects of decomposition types of smoothing cells in the strain smoothing technique are also discussed in terms of numerical stability and accuracy.