Existence of minimizers for the SDRI model in $\mathbb{R}^n$: Wetting and dewetting regimes with mismatch strain

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Main Authors: Kholmatov, Shokhrukh, Piovano, Paolo
Format: Preprint
Published: 2023
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author Kholmatov, Shokhrukh
Piovano, Paolo
author_facet Kholmatov, Shokhrukh
Piovano, Paolo
contents The existence and the regularity results obtained in [37] for the variational model introduced in [36] to study the optimal shape of crystalline materials in the setting of stress-driven rearrangement instabilities (SDRI) are extended from two dimensions to any dimensions $n\geq2$. The energy is the sum of the elastic and the surface energy contributions, which cannot be decoupled, and depend on configurational pairs consisting of a set and a function that model the region occupied by the crystal and the bulk displacement field, respectively. By following the physical literature, the ``driving stress'' due to the mismatch between the ideal free-standing equilibrium lattice of the crystal with respect to adjacent materials is included in the model by considering a discontinuous mismatch strain in the elastic energy. Since two-dimensional methods and the methods used in the previous literature where Dirichlet boundary conditions instead of the mismatch strain and only the wetting regime were considered, cannot be employed in this setting, we proceed differently, by including in the analysis the dewetting regime and carefully analyzing the fine properties of energy-equibounded sequences. This analysis allows to establish both a compactness property in the family of admissible configurations and the lower-semicontinuity of the energy with respect to the topology induced by the $L^1$-convergence of sets and a.e.\ convergence of displacement fields, so that the direct method can be applied. We also prove that our arguments work as well in the setting with Dirichlet boundary conditions.
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id arxiv_https___arxiv_org_abs_2305_10304
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Existence of minimizers for the SDRI model in $\mathbb{R}^n$: Wetting and dewetting regimes with mismatch strain
Kholmatov, Shokhrukh
Piovano, Paolo
Analysis of PDEs
Classical Analysis and ODEs
Optimization and Control
49J45, 28B20, 74G65
The existence and the regularity results obtained in [37] for the variational model introduced in [36] to study the optimal shape of crystalline materials in the setting of stress-driven rearrangement instabilities (SDRI) are extended from two dimensions to any dimensions $n\geq2$. The energy is the sum of the elastic and the surface energy contributions, which cannot be decoupled, and depend on configurational pairs consisting of a set and a function that model the region occupied by the crystal and the bulk displacement field, respectively. By following the physical literature, the ``driving stress'' due to the mismatch between the ideal free-standing equilibrium lattice of the crystal with respect to adjacent materials is included in the model by considering a discontinuous mismatch strain in the elastic energy. Since two-dimensional methods and the methods used in the previous literature where Dirichlet boundary conditions instead of the mismatch strain and only the wetting regime were considered, cannot be employed in this setting, we proceed differently, by including in the analysis the dewetting regime and carefully analyzing the fine properties of energy-equibounded sequences. This analysis allows to establish both a compactness property in the family of admissible configurations and the lower-semicontinuity of the energy with respect to the topology induced by the $L^1$-convergence of sets and a.e.\ convergence of displacement fields, so that the direct method can be applied. We also prove that our arguments work as well in the setting with Dirichlet boundary conditions.
title Existence of minimizers for the SDRI model in $\mathbb{R}^n$: Wetting and dewetting regimes with mismatch strain
topic Analysis of PDEs
Classical Analysis and ODEs
Optimization and Control
49J45, 28B20, 74G65
url https://arxiv.org/abs/2305.10304