“…On the other hand, the hybrid-Trefftz element methods is also an effective way for developing various FEMs in many fields, such as the T-Trefftz Voronoi cell finite elements, 24,25 and the hybrid-Trefftz FEMs for poroelastic media, 26 plate bending, 27,28 elastoplassticity, 29 Helmholtz problem, 30,31 heat conduction, 32 and so forth. In the past 10 years, Cen et al proposed two hybrid-Trefftz FEMs, a hybrid stress-function (HSF) [33][34][35][36][37][38][39] and a hybrid displacement-function (HDF) 33,[40][41][42][43][44][45] element methods for developing 2D plane and Mindlin-Reissner plate elements, respectively. The constructions of these element are simply extended from the original hybrid stress element proposed by Pian.…”