Article
Geochemistry & Geophysics
Fanzhen Meng, Louis Ngai Yuen Wong, Tianyang Guo
Summary: Rough fault surfaces play a dominant role in determining the mode of sliding. Stick-slip behavior occurs on all rough fractures during sliding, with stress drops and fault gouges increasing with normal stress. Micro-damage on post-shear surfaces includes powder-sized gouge, micro-cracks, and grain edge wear, increasing with normal stress. Different fault types have little discernible effect on stress drop. The study contributes to understanding the mechanics of dynamic geohazards associated with shear failure on rough faults or fracture surfaces.
Article
Geochemistry & Geophysics
Federica Paglialunga, Francois X. Passelegue, Nicolas Brantut, Fabian Barras, Mathias Lebihain, Marie Violay
Summary: The potential energy stored around faults during the inter-seismic period is released during earthquakes in the form of radiated energy, frictional dissipation, and fracture energy. The fracture energy is of primary importance in controlling the initiation, propagation, and arrest of seismic rupture. Seismological estimates of fracture energy show a clear dependence on slip, while recent experimental studies suggest fracture energy as a material property independent of seismic slip. Stick-slip experiments were performed to reconcile these observations and show that near-tip weakening controls rupture initiation, while long-tailed weakening enhances slip during propagation.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Engineering, Mechanical
S. V. Suknev
Summary: The paper presents the results of theoretical and experimental studies on brittle and quasi-brittle fracture of plaster plates with a circular hole under non-uniform compression. Modified fracture criteria based on the theory of critical distances are proposed to predict the critical load at the instant of crack initiation. Experimental verification indicates that the developed criteria can effectively describe the influence of hole size and boundary conditions on the fracture of quasi-brittle materials.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Geochemistry & Geophysics
Shahar Gvirtzman, Jay Fineberg
Summary: Frictional interfaces become unstable due to earthquake-like ruptures, which are similar to shear cracks. The nucleation of rupture determines the onset of friction and it is influenced by local stress and contact area topography. Nucleation events occur as 2D patches that expand at low velocities and are affected by the local stress level.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Materials Science, Multidisciplinary
Alexis Saez, Brice Lecampion, Pathikrit Bhattacharya, Robert C. Viesca
Summary: This study investigates the quasi-static growth of a fluid-driven shear crack on a fault interface, analyzing the rupture shape and area evolution under different injection scenarios and fault characteristics. The results provide insights into the propagation of stable (aseismic) ruptures and their relationship with fluid pressure increase.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Multidisciplinary Sciences
Tomoaki Suzudo, Ken-Ichi Ebihara, Tomohito Tsuru, Hideki Mori
Summary: Through large-scale atomistic simulations and stress intensity factor analyses, it was found that body-centered-cubic transition metals cleave along the {100} plane instead of the {110} plane with the lowest surface energy. The emission of dislocations from the crack fronts along the {110} cleavage plane explains this odd response. This highlights the importance of atomistic modeling at sufficiently large scales.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Multidisciplinary
Sai Li, Xin Lai, Lisheng Liu
Summary: In this work, the brittle fracture of shell structure was modeled using the Peridynamics Mindlin-Reissener shell theory. The stress-point method was used to improve numerical accuracy and eliminate numerical instability. A novel crack criterion based on explicit representation of the crack surface by stress points was proposed. Instead of using the critical stretch, the classic constitutive model in continuum mechanics was used to describe material failure. A concise crack simulation algorithm was provided to describe crack path and development. Numerical examples validated the accuracy and capability of the proposed model in representing crack propagation and branching.
CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES
(2022)
Article
Multidisciplinary Sciences
Anna Pomyalov, Fabian Barras, Thibault Roch, Efim A. Brener, Eran Bouchbinder
Summary: This article presents a theoretical study on slip pulses in realistic rate- and state-dependent frictional systems. The research shows that slip pulses are inherently unstable objects, but their dynamical evolution is closely linked to their stable counterparts. The study also reveals that slip pulses exist on a steady-state line and their non-steady dynamics are controlled by a single slow unstable mode. This theoretical picture is supported by large-scale simulations.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Engineering, Chemical
Jianbo Fei, Zhihao Liu, Muhammad Irslan Khalid, Yuxin Jie, Xiangsheng Chen
Summary: This study develops a dynamic model to describe the frictional-dilatancy behavior of underwater granular motion and verifies the accuracy of the model.
Article
Mechanics
Longbang Qing, Yang Li, Yimeng Su, Guowei Ma
Summary: The maximum resistance rate principle (MRRP) is proposed to characterize the instability of quasi-brittle fracture. It is observed that the unstable fracture occurs when the resistance rate reaches its maximum value under quasi-static loading conditions. The MRRP is elaborated based on the fracture resistance and resistance rate curve of a single edge cracked specimen, and it is verified by experimental data of three-point bending beams of different sizes. The influence of specimen geometry, size, and material parameters on fracture resistance and resistance rate is also discussed. The calculation results show that the resistance rate and external load reach their maximum values simultaneously in the critical state. Combined with the cohesive crack model, the MRRP effectively describes the unstable fracture of quasi-brittle materials, extending Griffith's theory of brittle fracture.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Mathematics, Applied
Ming Mei, Yang Wang
Summary: This paper considers two different kinds of degenerate n-degree Fisher-type equations with delays. The existence of traveling front is proved by different methods due to the difference of the reaction terms. Specifically, for one type of reaction term satisfying the weak quasimonotonicity condition, the existence result is obtained using the super-sub solution method and the fixed point theorem, while for the other type of reaction term, the existence conclusion is obtained using the monotone iteration method and the super-sub solution method.
APPLIED MATHEMATICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Dayoung Yoo, Mao Zhang, Changsoon Choi, Byungha Shin, Yoon-Hwae Hwang, Yangdo Kim, Dongyun Lee
Summary: The mechanical behavior and crack characteristics of GIGS films were studied, revealing higher fracture toughness than soda-lime glass, predominantly intergranular fracture, and the presence of Palmqvist radial and lateral cracks.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Chemistry, Physical
Angkur Jyoti Dipanka Shaikeea, Huachen Cui, Mark O'Masta, Xiaoyu Rayne Zheng, Vikram Sudhir Deshpande
Summary: Research shows that traditional elastic fracture mechanics and fracture testing methods are insufficient to characterize the fracture properties of advanced ultralight mechanical metamaterials. By combining numerical and asymptotic analysis, the study extends the concepts of elastic fracture mechanics to develop a general test and design protocol for truss-based metamaterials. This new framework provides a basis for understanding fracture in other elastic-brittle solids where traditional notions of fracture toughness may not apply.
Article
Multidisciplinary Sciences
Dmitry I. Garagash
Summary: The study develops a near tip solution to describe the unsteady dynamics of slip transients on rate- and state-dependent faults, and proposes using fracture energy to model these transients. It is shown that for faults induced by fluid injection, the propagation speed of a transient can be controlled by regulating the injection rate, and the maximum slip run-out distance is proportional to the total injection volume.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Nanoscience & Nanotechnology
R. Beygi, R. J. C. Carbas, E. A. S. Marques, A. Q. Barbosa, M. M. Kasaei, L. F. M. da Silva
Summary: This study used Friction Stir Welding (FSW) technique to create a clean and uniform Al/Cu interface and investigated the mechanism of pure brittle fracture. The results showed that multilayered fracture, intergranular fracture, and delamination of the Al/Al2Cu interface were all associated with brittle fracture.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2024)
Article
Materials Science, Multidisciplinary
Meng Wang, Mokhtar Adda-Bedia, John M. Kolinski, Jay Fineberg
Summary: The secondary structure of low-speed crack propagation in hydrogels has a significant influence on energy balance, and its implementation must account for local dynamic dissipation along the crack front.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Geochemistry & Geophysics
Shahar Gvirtzman, Jay Fineberg
Summary: Frictional interfaces become unstable due to earthquake-like ruptures, which are similar to shear cracks. The nucleation of rupture determines the onset of friction and it is influenced by local stress and contact area topography. Nucleation events occur as 2D patches that expand at low velocities and are affected by the local stress level.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Mechanics
Shai Feldfogel, Konstantinos Karapiperis, Jose Andrade, David S. Kammer
Summary: Topological Interlocking Structures (TIS) have been extensively researched, however, the effects of Young's modulus and the friction coefficient on the structural mechanics of centrally loaded TIS panels remain unclear. In this study, a parametric investigation is conducted to clarify the impact of these two parameters on the behavior and failure of centrally-loaded TIS panels. The findings indicate a linear relationship between structural response parameters and Young's modulus, saturation with the friction coefficient, and the saturated response as an upper-bound on the capacity of centrally loaded TIS panels reported in the literature. These findings contribute to a deeper understanding of interlocked structural forms.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Mechanics
Ioannis Koureas, Mohit Pundir, Shai Feldfogel, David S. Kammer
Summary: Topologically interlocked materials and structures, assemblies of unbonded interlocking building blocks, have shown exceptional mechanical properties. This study introduces a hierarchical approach inspired by biological systems to overcome limitations and enhance mechanical performance. By designing sinusoidal surface morphologies, numerical simulations demonstrate increased frictional strength and the ability to reach the theoretical limit of the structural carrying capacity with realistic friction coefficients.
JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME
(2023)
Article
Materials Science, Multidisciplinary
Miguel Castellano, Flavio Lorez, David S. Kammer
Summary: The onset of frictional sliding is initiated by the quasi-static growth of localized slip patches, which become unstable and dynamically continue to grow until the entire interface slides. The length of these patches, known as the nucleation length, can be calculated using stress criterion or energy criterion depending on whether the dominant process is yielding or fracture. However, both approaches have limitations in capturing the intermediate stages. In this study, numerical simulations show that high frictional heterogeneity enables a transition from a yielding-driven nucleation phase to a fracture-driven one, with the nature of the transition dependent on the correlation length of frictional strength and the difference in strength along the interface. The transition can lead to localized dynamic slip events, whose magnitude is affected by the correlation length and amplitude.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Editorial Material
Geochemistry & Geophysics
Ze'ev Reches, Jay Fineberg
Summary: Earthquakes are caused by dynamic fractures due to overstresses, not governed by the frictional properties of faults. Frictional interfaces can sustain a wide range of stresses before sliding, generating stress-fields and rupture dynamics. The values of stresses and energy dissipation are determined by fault frictional properties.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Xiaoyu Wang, Luca Dal Zilio, Julia K. Morgan, David S. Kammer
Summary: This study analyzed the nucleation and triggering processes of a 2-D strike-slip fault through Discrete Element Method simulations. The results showed that multiple pre-slip nucleation sites contribute to the final seismic event, and these sites can interact, leading to clock advance or cascade nucleation rupture processes. The study also revealed a new type of non-precursory aseismic slip, indicating a fault segment that appears weakly coupled but possesses the potential to be triggered seismically.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Engineering, Biomedical
Julia Kamml, Chun-Yu Ke, Claire Acevedo, David S. Kammer
Summary: Collagen derives its mechanical properties from its structure of cross-linked tropocollagen molecules. Enzymatic cross-links stabilize the fibril and improve material properties, while cross-linking AGEs impair the mechanical properties of collageneous tissues. The relationship between cross-link properties, density, and fibrillar behavior remains unclear.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2023)
Article
Multidisciplinary Sciences
Meng Wang, Songlin Shi, Jay Fineberg
Summary: Brittle materials were conventionally believed to have crack propagation speeds limited by the Rayleigh wave speed. However, our experimental study on brittle neo-hookean materials shows the existence of supershear tensile cracks, which can surpass the shear wave speed and even approach the dilatation wave speed. The dynamics of supershear cracks are controlled by different principles compared to classical cracks and this nonclassical fracture mode occurs at critical strain levels specific to the material, representing a fundamental shift in our understanding of fracture processes.
Article
Biology
James L. Rosenberg, William Woolley, Ihsan Elnunu, Julia Kamml, David S. Kammer, Claire Acevedo
Summary: Age and diabetes can cause oxidative reactions between glucose and collagen, resulting in the accumulation of advanced glycation end-products (AGEs) cross-links in collagenous tissues. Recent studies have shown that AGEs content is related to loss of bone quality and increased fracture risk, independent of bone mass, in aging and diabetes. One common pattern in both diabetic and age-related bone fragility is the increase of fibrillar collagen stiffness and loss of collagen-induced plasticity with AGE accumulation. This study focuses on the correlation between fluorescent AGEs content, collagen deformation mechanisms, and resistance to bone fracture at different scales.
Article
Physics, Multidisciplinary
Meng Wang, Mokhtar Adda-Bedia, Jay Fineberg
Summary: Slow cracks can be simple with a single fracture plane or segmented with multiple fracture planes. The merging of these planes forms steps along the fracture surfaces, which dynamically propagate within a crack front. Real-time measurements show that step dynamics significantly increase energy dissipation and change crack dynamics. The transition from stepped cracks to simple cracks occurs when their in-plane front lengths become equal and a perturbation momentarily changes step topology. These 3D crack dynamics challenge traditional understanding of fracture.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Engineering, Multidisciplinary
Shai Feldfogel, Konstantinos Karapiperis, Jose Andrade, David S. Kammer
Summary: The level-set-discrete-element-method (LS-DEM) overcomes the shape limitation of traditional discrete element method by utilizing a node-based surface discretization of grain boundary. It has been widely used in various granular mechanics applications. However, the original LS-DEM is sensitive to discretization and suffers from divergence of the response, especially in highly compressible problems. In this study, a methodologically-rigorous and computationally-efficient adapted formulation is proposed to solve this issue, which adopts the classical contact description of continuum mechanics.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Mechanics
Ioannis Koureas, Mohit Pundir, Shai Feldfogel, David S. Kammer
Summary: Topologically interlocked structures composed of interlocking blocks have been shown to exhibit high strength, energy dissipation, and crack arrest properties. Recent studies have found that non-planar blocks can achieve saturated structural response similar to commonly used friction properties in beam-like structures, and non-planar blocks cause a non-linear scaling of work-to-failure with peak strength and significant improvements in work-to-failure and ultimate deflection for slab-like structures.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2023)
Article
Engineering, Multidisciplinary
Flavio Lorez, Mohit Pundir, David S. Kammer
Summary: This article introduces a fully Eulerian finite element framework for modeling contact between elastic solids, specifically tailored for problems with evolving and intricate surfaces. The proposed approach uses a phase-field method that simplifies the modeling of evolving surfaces and introduces a new volumetric contact constraint to efficiently resolve the interpenetration of solids. Numerical examples demonstrate the validity and versatility of the method in accurately capturing complex solid-solid interactions.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Multidisciplinary Sciences
Zhichao Han, David S. Kammer, Olga Fink
Summary: Interacting particle systems play a key role in science and engineering. However, the complexity of these systems often hides the particle interactions. This study proposes an algorithm that combines machine learning and the Graph Networks framework to learn pairwise interactions in particle systems. The algorithm uses a deterministic operator to infer pairwise interactions consistent with underlying physical laws, achieving superior performance in inferring interactions and being consistent with physics.
