FreeHyTE: A Hybrid-Trefftz Finite Element Platform for Poroelastodynamic Problems

FreeHyTE is an open-source computational platform developed at the CERIS Research Centre, University of Lisbon. FreeHyTE employs hybrid-Trefftz finite elements, which are designed to avoid drawbacks of the conventional finite elements, such as the need of high mesh refinement under high frequency or short wavelength excitations. The key feature of the hybrid-Trefftz elements is that their approximation bases are problem-dependent and built using functions that satisfy exactly the homogeneous form of the differential equation governing the problem. FreeHyTE offers two modules for poroelastodynamic problems: The biphasic transient module and the triphasic transient module. In this paper, the theoretical background of the hybrid-Trefftz finite elements and their implementation in the FreeHyTE platform are presented, together with a simulation involving the propagation of a shock wave in a semi-infinite unsaturated medium to illustrate the different interfaces of the platform and some of its essential features.