Divergence-free finite element spaces for stress tensors

We construct finite element spaces of symmetric stress tensors that are exactly divergence-free. Moreover, their basis functions can be chosen so that they have small supports. These properties are highly desired in a number of important applications. Approximation properties of finite element spaces of divergence-free tensor functions are derived from properties of C1 finite elements.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).