An interface element based on the partition of unity

An alternative interface finite element is developed. By using the partition of unity property of finite element shape functions, discontinuous shape functions are added to the standard finite element basis. The interface behaviour is de-scribed by extra degrees of freedom at existing nodes, avoiding the need for ‘doubled nodes’. The element is kinematically equivalent to a conventional in-terface element but is more flexible because it allows the inclusion of interface surfaces within solid elements. In describing interface phenomena, the methodol-ogy proposed here makes possible the use of coarser meshes and it is completely insensitive to mesh topology. The new formulation is analysed throughly and comparisons are drawn with the conventional formulation