Hybrid-stress triangular finite element with enhanced performance for statics and dynamics

In this paper, we develop the mixed variational formulation with independent displacement, rotation and stress fields based on the work of Hughes and Brezzi (1989). However, we further suppress rotation field to obtain element superior performance for classical continuum case with hybrid-stress interpolation. The lowest order Whitney's interpolation or Raviart-Thomas vector space is employed to discretize stress field, which delivers superior performance by enforcing the continuity of traction field across element boundary. We further extend this optimal choice of hybrid-stress discrete approximation to dynamic analysis, by choosing the appropriate time-integration scheme that enforces stability for long-term computation. Several numerical simulations are given to illustrate an enhanced performance of the proposed element and algorithm. (C) 2020 Elsevier B.V. All rights reserved.