Voronoi Polygonal Hybrid Finite Elements with Boundary Integrals for Plane Isotropic Elastic Problems

Abstract

Polygonal finite elements with high level of geometric isotropy provide greater flexibility in mesh generation and material science involving topology change in material phase. In this study, a hybrid finite element model based on polygonal mesh is constructed by centroidal Voronoi tessellation for two-dimensional isotropic elastic problems and then is formulated with element boundary integrals only. For the present n-sided polygonal finite element, two independent fields are introduced: (i) displacement and stress fields inside the element; (ii) frame displacement field along the element boundary. The interior fields are approximated by fundamental solutions so that they exactly satisfy the governing equations to convert element domain integral in the two-field functional into element boundary integrals to reduce integration dimension. While the frame displacement field is approximated by the conventional shape functions to satisfy the conformity requirement between adjacent elements. The two independent fields are coupled by the weak functional to form the stiffness equation. This hybrid formulation enables the construction of n-sided polygons and extends the potential applications of finite elements to convex polygons of arbitrary order. Finally, five examples including patch tests in square domain, thick cylinder under internal pressure, beam bending and composite with clustered holes are provided to illustrate convergence, accuracy and capability of the present Voronoi polygonal finite elements Show more