Projection enhanced triangular finite element method

a novel FEM approach for polygonal elements

Authored by

Christian Sellmann, Peter Wriggers, Philipp Junker

Abstract

In this work, we introduce the Projection Enhanced Triangular Finite Element Method (PET-FEM), a finite element formulation for polygonal meshes. The method relies on a FEM sub-mesh, while the internal degrees of freedom are recovered by a least-squares projection operator. This yields an implementation that is simple, flexible, and free of problem-dependent parameters. For higher-order PET-FEM, the formulation admits a serendipity-style reduction of internal degrees of freedom and shows improved robustness under mesh distortion compared to classical FEM serendipity elements. We further propose a first-order element that blends VEM and PET-FEM to obtain a computationally inexpensive, locking-free discretization. We benchmark our approach for the Poisson equation and for standard benchmarks in structural mechanics, including linear and nonlinear cases (e.g., Cook’s membrane and a punch test). The method achieves optimal convergence across all tests, with improved accuracy of the first-order element in locking-dominated problems.

Details

Organisation(s)
Institute of Continuum Mechanics
International RTG 2657: Computational Mechanics Techniques in High Dimensions
Type
Article
Journal
Computer Methods in Applied Mechanics and Engineering
Volume
454
ISSN
0045-7825
Publication date
25.02.2026
Publication status
E-pub ahead of print
Peer reviewed
Yes
ASJC Scopus subject areas
Computational Mechanics, Mechanics of Materials, Mechanical Engineering, General Physics and Astronomy, Computer Science Applications
Electronic version(s)
https://doi.org/10.1016/j.cma.2026.118838 (Access: Open )
 

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