Improved Coupling of Finite Shell Elements and 3D Boundary Elements

A strategy for the mixed-dimensional coupling of finite shell elements and 3D boundary elements is presented. The stiffness formulation for the boundary element domain is generated by the 3D symmetric Galerkin boundary element method and thus can be assembled to the global finite element formulation. Based on the equality of work at the coupling interface, coupling equations in an integral sense are derived for curved coupling interfaces and formulated as multipoint constraints in terms of kinematic quantities. Several examples show the highly accurate results compared to a strict kinematic coupling technique.