A low-order nonconforming method for linear elasticity on general meshes
For computational mechanics researchers, this provides a stable low-order method on general meshes, though it is an incremental extension of existing HHO methods.
This work presents a low-order nonconforming method for linear elasticity on general meshes by extending the Hybrid High-Order method to polynomial degree k=0, achieving locking-free error estimates that converge as h in energy norm and h^2 in L2 norm for smooth solutions.
In this work we construct a low-order nonconforming approximation method for linear elasticity problems supporting general meshes and valid in two and three space dimensions. The method is obtained by hacking the Hybrid High-Order method, that requires the use of polynomials of degree $k\ge1$ for stability. Specifically, we show that coercivity can be recovered for $k=0$ by introducing a novel term that penalises the jumps of the displacement reconstruction across mesh faces. This term plays a key role in the fulfillment of a discrete Korn inequality on broken polynomial spaces, for which a novel proof valid for general polyhedral meshes is provided. Locking-free error estimates are derived for both the energy- and the $L^2$-norms of the error, that are shown to convergence, for smooth solutions, as $h$ and $h^2$, respectively (here, $h$ denotes the meshsize). A thorough numerical validation on a complete panel of two- and three-dimensional test cases is provided.