Yet another best approximation isotropic elasticity tensor in plane strain

Fuente: arXiv
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Autori principali: Voss, Jendrik, Gourgiotis, Panos, Lewintan, Peter, Sky, Adam, Neff, Patrizio
Natura: Preprint
Pubblicazione: 2024
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author Voss, Jendrik
Gourgiotis, Panos
Lewintan, Peter
Sky, Adam
Neff, Patrizio
author_facet Voss, Jendrik
Gourgiotis, Panos
Lewintan, Peter
Sky, Adam
Neff, Patrizio
contents For plane strain linear elasticity, given any anisotropic elasticity tensor $\mathbb{C}_{\rm aniso}$, we determine a best approximating isotropic counterpart $\mathbb{C}_{\rm iso}$. This is not done by using a distance measure on the space of positive definite elasticity tensors (Euclidean or logarithmic distance) but by considering two simple isotropic analytic solutions (center of dilatation and concentrated couple) and best fitting these radial solutions to the numerical anisotropic solution based on $\mathbb{C}_{\rm aniso}$. The numerical solution is done via a finite element calculation, and the fitting via a subsequent quadratic error minimization. Thus, we obtain the two Lamé-moduli $μ$, $λ$ (or $μ$ and the bulk-modulus $κ$) of $\mathbb{C}_{\rm aniso}$. We observe that our so-determined isotropic tensor $\mathbb{C}_{\rm iso}$ coincides with neither the best logarithmic fit of Norris nor the best Euclidean fit. Our result calls into question the very notion of a best-fit isotropic elasticity tensor to a given anisotropic material.
format Preprint
id arxiv_https___arxiv_org_abs_2406_19914
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Yet another best approximation isotropic elasticity tensor in plane strain
Voss, Jendrik
Gourgiotis, Panos
Lewintan, Peter
Sky, Adam
Neff, Patrizio
Analysis of PDEs
Numerical Analysis
74A10, 74B05, 74M25
For plane strain linear elasticity, given any anisotropic elasticity tensor $\mathbb{C}_{\rm aniso}$, we determine a best approximating isotropic counterpart $\mathbb{C}_{\rm iso}$. This is not done by using a distance measure on the space of positive definite elasticity tensors (Euclidean or logarithmic distance) but by considering two simple isotropic analytic solutions (center of dilatation and concentrated couple) and best fitting these radial solutions to the numerical anisotropic solution based on $\mathbb{C}_{\rm aniso}$. The numerical solution is done via a finite element calculation, and the fitting via a subsequent quadratic error minimization. Thus, we obtain the two Lamé-moduli $μ$, $λ$ (or $μ$ and the bulk-modulus $κ$) of $\mathbb{C}_{\rm aniso}$. We observe that our so-determined isotropic tensor $\mathbb{C}_{\rm iso}$ coincides with neither the best logarithmic fit of Norris nor the best Euclidean fit. Our result calls into question the very notion of a best-fit isotropic elasticity tensor to a given anisotropic material.
title Yet another best approximation isotropic elasticity tensor in plane strain
topic Analysis of PDEs
Numerical Analysis
74A10, 74B05, 74M25
url https://arxiv.org/abs/2406.19914