Hybrid finite element method based on novel general solutions for helmholtz-type problems

Abstract

This paper presents a hybrid finite element model (FEM) with a new type of general solution as interior trial functions, named as HGS-FEM. A variational functional corresponding to the proposed general solution is then constructed for deriving the element stiffness matrix of the proposed element model and the corresponding existence of extremum is verified. Then the assumed intra-element potential field is constructed by a linear combination of novel general solutions at the points on the element boundary under consideration. Furthermore, the independent frame field is introduced to guarantee the intra-element continuity. The present scheme inherits the advantages of hybrid Trefftz FEM (HT-FEM) over the conventional FEM and BEM, and avoids the difficulty in choosing appropriate terms of Trefftz functions in HT-FEM and also removing the troublesome for determining fictitious boundary in hybrid fundamental solution-based FEM (HFS-FEM). The efficiency and accuracy of the proposed model are assessed through several numerical examples.