Quenched disorder and instability control dynamic fracture in three dimensions

Fuente: arXiv
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Autori principali: Lubomirsky, Yuri, Bouchbinder, Eran
Natura: Preprint
Pubblicazione: 2023
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author Lubomirsky, Yuri
Bouchbinder, Eran
author_facet Lubomirsky, Yuri
Bouchbinder, Eran
contents Materials failure in 3D still poses basic challenges. We study 3D brittle crack dynamics using a phase-field approach, where Gaussian quenched disorder in the fracture energy is incorporated. Disorder is characterized by a correlation length $R$ and strength $σ$. We find that the mean crack velocity $v$ is bounded by a limiting velocity, which is smaller than the homogeneous material's prediction and decreases with $σ$. It emerges from a dynamic renormalization of the fracture energy with increasing crack driving force $G$, resembling a critical point, due to an interplay between a 2D branching instability and disorder. At small $G$, the probability of localized branching on a scale $R$ is super-exponentially small. With increasing $G$ this probability quickly increases, leading to misty fracture surfaces, yet the associated extra dissipation remains small. As $G$ is further increased, branching-related lengthscales become dynamic and persistently increase, leading to hackle-like structures and to a macroscopic contribution to the fracture surface. The latter dynamically renormalizes the actual fracture energy until eventually any increase in $G$ is balanced by extra fracture surface, with no accompanying increase in $v$. Finally, branching width reaches the system's thickness such that 2D symmetry is statistically restored. Our findings are consistent with a broad range of experimental observations.
format Preprint
id arxiv_https___arxiv_org_abs_2311_11692
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Quenched disorder and instability control dynamic fracture in three dimensions
Lubomirsky, Yuri
Bouchbinder, Eran
Materials Science
Disordered Systems and Neural Networks
Soft Condensed Matter
Pattern Formation and Solitons
Materials failure in 3D still poses basic challenges. We study 3D brittle crack dynamics using a phase-field approach, where Gaussian quenched disorder in the fracture energy is incorporated. Disorder is characterized by a correlation length $R$ and strength $σ$. We find that the mean crack velocity $v$ is bounded by a limiting velocity, which is smaller than the homogeneous material's prediction and decreases with $σ$. It emerges from a dynamic renormalization of the fracture energy with increasing crack driving force $G$, resembling a critical point, due to an interplay between a 2D branching instability and disorder. At small $G$, the probability of localized branching on a scale $R$ is super-exponentially small. With increasing $G$ this probability quickly increases, leading to misty fracture surfaces, yet the associated extra dissipation remains small. As $G$ is further increased, branching-related lengthscales become dynamic and persistently increase, leading to hackle-like structures and to a macroscopic contribution to the fracture surface. The latter dynamically renormalizes the actual fracture energy until eventually any increase in $G$ is balanced by extra fracture surface, with no accompanying increase in $v$. Finally, branching width reaches the system's thickness such that 2D symmetry is statistically restored. Our findings are consistent with a broad range of experimental observations.
title Quenched disorder and instability control dynamic fracture in three dimensions
topic Materials Science
Disordered Systems and Neural Networks
Soft Condensed Matter
Pattern Formation and Solitons
url https://arxiv.org/abs/2311.11692