Intrinsic mixed finite element methods for linear Cosserat elasticity

Fuente: arXiv
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Main Authors: Dziubek, Andrea, Hu, Kaibo, Karow, Michael, Neunteufel, Michael
Format: Preprint
Published: 2024
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author Dziubek, Andrea
Hu, Kaibo
Karow, Michael
Neunteufel, Michael
author_facet Dziubek, Andrea
Hu, Kaibo
Karow, Michael
Neunteufel, Michael
contents We propose two parameter-robust mixed finite element methods for linear Cosserat elasticity. The Cosserat coupling constant $μ_c$, connecting the displacement $u$ and rotation vector $ω$, leads to possible locking phenomena in finite element methods. The formal limit of $μ_c\to\infty$ enforces the constraint $\frac{1}{2}\operatorname{curl} u = ω$ and leads to the fourth-order couple stress problem. Viewing the linear Cosserat model as the Hodge-Laplacian problem of a twisted de~Rham complex, we derive structure-preserving distributional finite element spaces, where the limit constraint is fulfilled in the discrete setting. Applying the mass conserving mixed stress (MCS) method for the rotations, the resulting scheme is robust in $μ_c$. Combining it with the tangential-displacement normal-normal-stress (TDNNS) method for the displacement part, we obtain additional robustness in the nearly incompressible regime and for anisotropic structures. Using a post-processing scheme for the rotations, we prove optimal convergence rates independent of the Cosserat coupling constant $μ_c$. We demonstrate the performance of the proposed methods in several numerical benchmark examples.
format Preprint
id arxiv_https___arxiv_org_abs_2410_14176
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Intrinsic mixed finite element methods for linear Cosserat elasticity
Dziubek, Andrea
Hu, Kaibo
Karow, Michael
Neunteufel, Michael
Numerical Analysis
65N30 (Primary) 74S05 (Secondary)
We propose two parameter-robust mixed finite element methods for linear Cosserat elasticity. The Cosserat coupling constant $μ_c$, connecting the displacement $u$ and rotation vector $ω$, leads to possible locking phenomena in finite element methods. The formal limit of $μ_c\to\infty$ enforces the constraint $\frac{1}{2}\operatorname{curl} u = ω$ and leads to the fourth-order couple stress problem. Viewing the linear Cosserat model as the Hodge-Laplacian problem of a twisted de~Rham complex, we derive structure-preserving distributional finite element spaces, where the limit constraint is fulfilled in the discrete setting. Applying the mass conserving mixed stress (MCS) method for the rotations, the resulting scheme is robust in $μ_c$. Combining it with the tangential-displacement normal-normal-stress (TDNNS) method for the displacement part, we obtain additional robustness in the nearly incompressible regime and for anisotropic structures. Using a post-processing scheme for the rotations, we prove optimal convergence rates independent of the Cosserat coupling constant $μ_c$. We demonstrate the performance of the proposed methods in several numerical benchmark examples.
title Intrinsic mixed finite element methods for linear Cosserat elasticity
topic Numerical Analysis
65N30 (Primary) 74S05 (Secondary)
url https://arxiv.org/abs/2410.14176