HDG methods for elastodynamics

TL;DR

This paper develops and analyzes hybridizable discontinuous Galerkin methods for solving time-harmonic linear elasticity problems, ensuring optimal convergence and efficient implementation for various polynomial degrees.

Contribution

The paper introduces new HDG methods for elastodynamics that enforce stress symmetry and provide systematic error analysis, including variants optimized for different polynomial degrees.

Findings

Methods achieve optimal convergence rates.

Numerical experiments confirm theoretical error estimates.

Variants offer trade-offs in computational efficiency.

Abstract

We derive and analyze a hybridizable discontinuous Galerkin (HDG) method for approximating weak solutions to the equations of time-harmonic linear elasticity on a bounded Lipschitz domain in three dimensions. The real symmetry of the stress tensor is strongly enforced and its coefficients as well as those of the displacement vector field are approximated simultaneously at optimal convergence with respect to the choice of approximating spaces, wavenumber, and mesh size. Sufficient conditions are given so that the system is indeed transferable onto a global hybrid variable that, for larger polynomial degrees, may be approximated via a smaller-dimensional space than the original variables. We construct several variants of this method and discuss their advantages and disadvantages, and give a systematic approach to the error analysis for these methods. We touch briefly on the application of this error analysis to the time-dependent problem, and finally, we examine two different implementations of the method over various polynomial degrees and numerically demonstrate the convergence properties proven herein.