This is the peer reviewed version of the following article: Sevilla, R., Giacomini, M., Karkoulias, A., Huerta, A. A superconvergent hybridisable discontinuous Galerkin method for linear elasticity. "International journal for numerical methods in engineering", 12 Octubre 2018, vol. 116, núm. 2, p. 91-116, which has been published in final form at https://doi.org/10.1002/nme.5916. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

The first superconvergent hybridisable discontinuous Galerkin method for linear elastic problems capable of using the same degree of approximation for both the primal and mixed variables is presented. The key feature of the method is the strong imposition of the symmetry of the stress tensor by means of the well known and extensively used Voigt notation, circumventing the use of complex mathematical concepts to enforce the symmetry of the stress tensor either weakly or strongly. A novel procedure to construct element by element a superconvergent postprocessed displacement is proposed. Contrary to other hybridisable discontinuous Galerkin formulations, the methodology proposed here is able to produce a superconvergent displacement field for low-order approximations. The resulting method is robust and locking-free in the nearly incompressible limit. An extensive set of numerical examples is utilised to provide evidence of the optimality of the method and its superconvergent properties in two and three dimensions and for different element types.

Peer Reviewed