Thermal analysis of multilayer coated fiber-reinforced composites by the hybrid Trefftz finite element method

Abstract A hybrid Trefftz finite element method (HT-FEM) that incorporates the details of heterogeneity, is proposed for capturing the thermal behavior of multilayer coated fiber-reinforced composites. The main idea is to build-up independent two-temperature fields within the domain and along the boundary of the polygonal element. Each element domain is embedded by a fiber with multiple coatings. The Trefftz complete functions analytically satisfying the heat transfer equations are used as intra-element trial functions for the individual phases (fiber, coating and matrix) in a recursive form. The continuity of temperature between adjacent constituent phases is consequently enforced. After introducing the divergence theorem into the single hybrid functional, the degrees of freedom appear only along the element boundaries. This enables polygonal elements to be easily constructed for modeling the heterogeneous materials. Close attention is paid to evaluate the accuracy and efficiency of the HT-FEM through three numerical examples which involve mono- or multilayer coated fibers in different spatial distributions.