Implementation of arbitrary polyhedral elements for automatic dynamic analyses of three-dimensional structures.

The transition from the geometry to the mesh can be rather difficult, manual and time-consuming, especially for the large scale complex structures. The procedure of mesh generation needs massive human intervention making the automatic engineering analyses of structures from CAD geometry models hardly possible. This paper focuses on implementing a polyhedron element with arbitrary convex topology based on the Scaled Boundary Finite Element Method (SBFEM) in ABAQUS on the strength of the interface of UEL (the subroutine to define a general user-defined element) for automatic dynamic analyses of three-dimensional structures. This implementation empowers ABAQUS to analyze any model with arbitrary polyhedron elements. When the geometry of a structure is obtained from CAD, the dynamic analyses can be launched seamlessly and automatically. Cases of a cantilever subjected to a dynamic harmonic excitation with the traditional hexahedron element and this polyhedron element are compared to verify the accuracy of the UEL. Taking a practical example of the Soil-Structure Interaction analysis of a Nuclear Power Plant, the applicability and performance of this implementation are tested. The results of the two examples confirm that this polyhedron element based on SBFEM can be more accurate using much less degrees of freedom and its implementation in ABAQUS is robust and compatible.