Mixed displacement–pressure formulations and suitable finite elements for multimaterial problems with compressible and incompressible models

Kadapa, Chennakesava

Abstract

Multimaterial problems in linear and nonlinear elasticity are some of the least explored using mixed finite element formulations with higher-order elements. The fundamental issue in adapting the mixed displacement–pressure formulations with linear and higher-order continuous elements for the pressure field is their inability to capture pressure and stress jumps across material interfaces. In this paper, for the first time in literature, we perform comprehensive studies of multimaterial problems in elasticity consisting of compressible and incompressible material models using the mixed displacement–pressure formulation to assess the performance of different element types in accurately resolving pressure fields within the domains and pressure jumps across material interfaces. In particular, inf–sup stable displacement–pressure combinations with element-wise discontinuous pressure for triangular and tetrahedral elements are considered and their performance is assessed along with the Q1/P0 element and Taylor–Hood elements using several numerical examples. The results show that Taylor–Hood elements fail to capture the stress jumps due to the continuity of DOFs across elements, the Crouzeix–Raviart (P2b/P1dc) element yields substantially poor pressure fields despite a significant increase in pressure degrees of freedom and that the P3/P1dc element produces superior quality results fields when compared with the P2b/P1dc element.

Citation

Kadapa, C. (2024). Mixed displacement–pressure formulations and suitable finite elements for multimaterial problems with compressible and incompressible models. Computer Methods in Applied Mechanics and Engineering, 432(Part A), Article 117354. https://doi.org/10.1016/j.cma.2024.117354

• Journal Article Type: Article
• Acceptance Date: Sep 2, 2024
• Online Publication Date: Sep 10, 2024
• Publication Date: Dec 1, 2024
• Deposit Date: Sep 10, 2024
• Publicly Available Date: Sep 10, 2024
• Journal: Computer Methods in Applied Mechanics and Engineering
• Print ISSN: 0045-7825
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 432
• Issue: Part A
• Article Number: 117354
• DOI: https://doi.org/10.1016/j.cma.2024.117354
• Keywords: Finite element method, Hyperelasticity, Incompressibility, Mixed formulation, Stress discontinuity