The investigation of phase transitions in materials under high pressure has been a prominent topic in the field of high-pressure science. Tin undergoes several phase transformations (fcc (α)→bct (β)→bct (γ)→bco→bcc→hcp) with the pressure increase, which make it an ideal material for investigating the mechanisms of phase transitions under high pressure. In this work, the flyer impact perturbation method was employed to investigate the equivalent viscosity of tin under high pressure. By exploiting the decay propagation characteristics of perturbation shock waves and combining them with numerical simulations of two-dimensional flow fields, the equivalent viscosity coefficient of tin is 90–1980 Pa s at 25–75 GPa. Their significant segmented variation characteristics with pressure are in good agreement with the phase distribution characteristics of tin in certain pressure regions. It is clear that there is a strong correlation between the equivalent viscosity change characteristics and structural phase transitions of corresponding material under high pressure. This work firstly provides new direct evidence for predicting the possible phase transition of materials under high pressure.
{"title":"The relationship between the equivalent viscosity of tin (Sn) and its phase transition under shock compression","authors":"Chongyang Zeng, Jiajun Liu, Ziying Liang, Xiao Wu, ChaoCheng Wei, Xiaojuan Ma","doi":"10.1016/j.mechmat.2025.105549","DOIUrl":"10.1016/j.mechmat.2025.105549","url":null,"abstract":"<div><div>The investigation of phase transitions in materials under high pressure has been a prominent topic in the field of high-pressure science. Tin undergoes several phase transformations (fcc (α)→bct (β)→bct (γ)→bco→bcc→hcp) with the pressure increase, which make it an ideal material for investigating the mechanisms of phase transitions under high pressure. In this work, the flyer impact perturbation method was employed to investigate the equivalent viscosity of tin under high pressure. By exploiting the decay propagation characteristics of perturbation shock waves and combining them with numerical simulations of two-dimensional flow fields, the equivalent viscosity coefficient of tin is 90–1980 Pa s at 25–75 GPa. Their significant segmented variation characteristics with pressure are in good agreement with the phase distribution characteristics of tin in certain pressure regions. It is clear that there is a strong correlation between the equivalent viscosity change characteristics and structural phase transitions of corresponding material under high pressure. This work firstly provides new direct evidence for predicting the possible phase transition of materials under high pressure.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105549"},"PeriodicalIF":4.1,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Porous materials offer the possibility to optimize shock wave mitigation by monitoring, with additive manufacturing, the pore configuration (volume fraction, shape and spatial distribution of voids). Therefore, it is of interest to uncover the relationship between void configuration and shock wave response. In this paper we develop an analysis of planar plastic shock waves generated in porous aluminum by the impact of a projectile. Methodology and results can be easily extended to other materials. We focus specially on the relationship between shock-width and void-shape for given impact velocity and fixed initial volume fraction and spatial distribution of voids. We consider a Finite Element modeling of a periodic material with axisymmetric configuration. Each unit cell contains a spheroidal void with symmetry axis aligned along the impact direction. It is shown that the shock width is significantly affected by the process of void collapse. This process appears to be quite different for flat (oblate) and elongated (prolate) voids. For both types of voids, we analyze how the process and the speed of void closure are affected by the void aspect ratio, and we demonstrate that the shock width is increased by slowing down the speed of void collapse. Effects of the void aspect ratio on the void closure speed and on the shock-width are quantified. We explain why the slowest void closure and the largest shock width are obtained for spherical voids.
{"title":"Effect of pore shape on steady plastic shockwaves and collapse dynamics in porous metals","authors":"Alain Molinari , Eyass Massarwa , Christophe Czarnota","doi":"10.1016/j.mechmat.2025.105551","DOIUrl":"10.1016/j.mechmat.2025.105551","url":null,"abstract":"<div><div>Porous materials offer the possibility to optimize shock wave mitigation by monitoring, with additive manufacturing, the pore configuration (volume fraction, shape and spatial distribution of voids). Therefore, it is of interest to uncover the relationship between void configuration and shock wave response. In this paper we develop an analysis of planar plastic shock waves generated in porous aluminum by the impact of a projectile. Methodology and results can be easily extended to other materials. We focus specially on the relationship between shock-width and void-shape for given impact velocity and fixed initial volume fraction and spatial distribution of voids. We consider a Finite Element modeling of a periodic material with axisymmetric configuration. Each unit cell contains a spheroidal void with symmetry axis aligned along the impact direction. It is shown that the shock width is significantly affected by the process of void collapse. This process appears to be quite different for flat (oblate) and elongated (prolate) voids. For both types of voids, we analyze how the process and the speed of void closure are affected by the void aspect ratio, and we demonstrate that the shock width is increased by slowing down the speed of void collapse. Effects of the void aspect ratio on the void closure speed and on the shock-width are quantified. We explain why the slowest void closure and the largest shock width are obtained for spherical voids.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105551"},"PeriodicalIF":4.1,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Living systems exhibit remarkable resilience to withstand diverse and often extreme environmental conditions. Central to this adaptability are mechanisms like homeostasis and epigenesis. The first refers to the ability of organisms to maintain internal stability amidst external fluctuations, while the second provides organisms with the capacity for adjusting their homeostatic response to persistent environmental stressors. A thorough understanding of these physiological processes is essential for preventing disease, maintaining health, and facilitating recovery.
We present here a conceptual framework in which homeostasis is modeled as a robust, adaptive, spatially-dependent control system, where the adaptation block is regulated by epigenetic changes. This approach offers a powerful and integrated tool to predict the point-wise evolution of macroscopic biological systems due to short and long term environmental perturbations. Conceptual and methodological similarities with well-established predictive tools in Continuum Physics, particularly Continuum Mechanics, with internal variables are also highlighted.
After reviewing the problem and stating the equations in two different examples: thermoregulation to illustrate short term homeostasis, and tumor cell plasticity to clarify epigenetic adaptation, we analyze bone remodeling. This is a classic homeostatic process where bone mass and architecture are locally and dynamically regulated in response to mechanical demands and micro-damage accumulation. In here, we assimilate bone remodeling to a damage–repair problem, employing concepts and tools from time-dependent Continuum Damage Mechanics. The possibility of long term adaptation of this regulatory process by epigenesis-induced changes in the control signal reference is also analyzed. This permits to adjust bone microstructure to permanent changes in the mechanical conditions as happens under long periods of low gravity.
This modeling framework provides a valuable quantitative tool for investigating how organisms cope with environmental challenges, evolve their adaptive response over time, and potentially develop diseases when these regulatory mechanisms fail, offering new avenues for research at the intersection of Biology, Medicine and Engineering.
{"title":"A phenomenological mathematical framework to model homeostasis as a robust, adaptive control system. Similarities with continuum nonlinear physics with internal variables","authors":"Manuel Doblaré , Marina Pérez-Aliacar , Jacobo Ayensa-Jiménez , Mehran Ashrafi","doi":"10.1016/j.mechmat.2025.105546","DOIUrl":"10.1016/j.mechmat.2025.105546","url":null,"abstract":"<div><div>Living systems exhibit remarkable resilience to withstand diverse and often extreme environmental conditions. Central to this adaptability are mechanisms like homeostasis and epigenesis. The first refers to the ability of organisms to maintain internal stability amidst external fluctuations, while the second provides organisms with the capacity for adjusting their homeostatic response to persistent environmental stressors. A thorough understanding of these physiological processes is essential for preventing disease, maintaining health, and facilitating recovery.</div><div>We present here a conceptual framework in which homeostasis is modeled as a robust, adaptive, spatially-dependent control system, where the adaptation block is regulated by epigenetic changes. This approach offers a powerful and integrated tool to predict the point-wise evolution of macroscopic biological systems due to short and long term environmental perturbations. Conceptual and methodological similarities with well-established predictive tools in Continuum Physics, particularly Continuum Mechanics, with internal variables are also highlighted.</div><div>After reviewing the problem and stating the equations in two different examples: thermoregulation to illustrate short term homeostasis, and tumor cell plasticity to clarify epigenetic adaptation, we analyze bone remodeling. This is a classic homeostatic process where bone mass and architecture are locally and dynamically regulated in response to mechanical demands and micro-damage accumulation. In here, we assimilate bone remodeling to a damage–repair problem, employing concepts and tools from time-dependent Continuum Damage Mechanics. The possibility of long term adaptation of this regulatory process by epigenesis-induced changes in the control signal reference is also analyzed. This permits to adjust bone microstructure to permanent changes in the mechanical conditions as happens under long periods of low gravity.</div><div>This modeling framework provides a valuable quantitative tool for investigating how organisms cope with environmental challenges, evolve their adaptive response over time, and potentially develop diseases when these regulatory mechanisms fail, offering new avenues for research at the intersection of Biology, Medicine and Engineering.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105546"},"PeriodicalIF":4.1,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-17DOI: 10.1016/j.mechmat.2025.105550
Linli Zhu , Kaiyue Fu , Zizheng Guo , Bin Gan , Jitang Fan , Ligang Sun , Xiaogui Wang
The gradient nanostructured metallic materials possess the excellent mechanical properties, including the high strength, good elongation and fatigue performance. In this work, a microstructure and mechanism-based constitutive model is established to explore the strength-ductility relation and fatigue properties of the gradient nanostructured 316L stainless steel (316LSS) through considering the various microstructure distributions. Inspired by the experimental observation of distinguish distribution of nanograined austenite and martensite phase, nanotwinned austenite grains and coarse grains, the micromechanical constitutive model is developed to describe the axial tensile deformation behaviors of the gradient-nanostructured 316LSS, involving the flow stress for different phases and the contribution of microcracks on plastic deformation. The simulation results demonstrate that the proposed constitutive model enables to describe the experimental results successfully, including the yield strength, strain hardening and ductility. Additionally, with considering the gradient distribution evolution of microstructures and the damage evolution during cyclic deformation behavior, the fatigue constitutive model for gradient nanostructured metals is developed to describe the uniaxial tensile cycle characteristics of gradient nanostructured 316LSS. The numerical results show that the strain-controlled cyclic deformation behavior of gradient nanostructured stainless steel can be well described, including the cyclic softening and secondary hardening behaviors. The proposed fatigue constitutive model is also applied to forecast the fatigue behavior of the various amplitudes of the stress and the strain, and the various distribution of the fine-grained martensitic phase, nanotwinned austenite grains and coarse grains. These findings could provide the theoretical basis for regulating the strength-ductility relation and fatigue properties of gradient nanostructured metals.
{"title":"Constitutive modeling of the elastoplastic and fatigue behaviors of gradient-nanostructured 316L stainless steels with hierarchical structures","authors":"Linli Zhu , Kaiyue Fu , Zizheng Guo , Bin Gan , Jitang Fan , Ligang Sun , Xiaogui Wang","doi":"10.1016/j.mechmat.2025.105550","DOIUrl":"10.1016/j.mechmat.2025.105550","url":null,"abstract":"<div><div>The gradient nanostructured metallic materials possess the excellent mechanical properties, including the high strength, good elongation and fatigue performance. In this work, a microstructure and mechanism-based constitutive model is established to explore the strength-ductility relation and fatigue properties of the gradient nanostructured 316L stainless steel (316LSS) through considering the various microstructure distributions. Inspired by the experimental observation of distinguish distribution of nanograined austenite and martensite phase, nanotwinned austenite grains and coarse grains, the micromechanical constitutive model is developed to describe the axial tensile deformation behaviors of the gradient-nanostructured 316LSS, involving the flow stress for different phases and the contribution of microcracks on plastic deformation. The simulation results demonstrate that the proposed constitutive model enables to describe the experimental results successfully, including the yield strength, strain hardening and ductility. Additionally, with considering the gradient distribution evolution of microstructures and the damage evolution during cyclic deformation behavior, the fatigue constitutive model for gradient nanostructured metals is developed to describe the uniaxial tensile cycle characteristics of gradient nanostructured 316LSS. The numerical results show that the strain-controlled cyclic deformation behavior of gradient nanostructured stainless steel can be well described, including the cyclic softening and secondary hardening behaviors. The proposed fatigue constitutive model is also applied to forecast the fatigue behavior of the various amplitudes of the stress and the strain, and the various distribution of the fine-grained martensitic phase, nanotwinned austenite grains and coarse grains. These findings could provide the theoretical basis for regulating the strength-ductility relation and fatigue properties of gradient nanostructured metals.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105550"},"PeriodicalIF":4.1,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1016/j.mechmat.2025.105547
Stephen Melly, Aleksander Czekanski
Constitutive models are crucial for predicting and optimizing complex material systems via numerical techniques such as the finite element method. In addition to large nonlinear elastic deformation, strain rate sensitivity is an intrinsic mechanical characteristic of soft materials, including elastomers, hydrogels, and biological tissues. Accurate mathematical formulations describing these mechanical characteristics ensure time and cost efficiency, reliability, and improved design performance. Several modeling approaches have been proposed in the literature. The external state variable approach is advantageous thanks to its relative ease in numerical implementation and satisfaction of the principles of thermodynamics. This study presents the predictive capabilities of three different forms of viscous potential functions over five soft materials, including polyvinyl alcohol hydrogel, optically clear adhesive, elastomeric polyurethane, very high bond 4910, and styrene-ethylene-butylene-styrene gel. Accuracy of the predictions was quantified using the coefficient of determination and the normalized mean absolute difference. Results demonstrated that a recently proposed viscous potential function, named model 3 in this study, is relatively accurate and versatile in describing the rate-dependent behavior of soft materials. The results presented herein help researchers and design engineers to select the right models, provide insights into existing limitations, and guide the development of improved and more versatile models.
{"title":"Predictive performance of viscous potential functions for modeling strain rate sensitivity of soft materials","authors":"Stephen Melly, Aleksander Czekanski","doi":"10.1016/j.mechmat.2025.105547","DOIUrl":"10.1016/j.mechmat.2025.105547","url":null,"abstract":"<div><div>Constitutive models are crucial for predicting and optimizing complex material systems via numerical techniques such as the finite element method. In addition to large nonlinear elastic deformation, strain rate sensitivity is an intrinsic mechanical characteristic of soft materials, including elastomers, hydrogels, and biological tissues. Accurate mathematical formulations describing these mechanical characteristics ensure time and cost efficiency, reliability, and improved design performance. Several modeling approaches have been proposed in the literature. The external state variable approach is advantageous thanks to its relative ease in numerical implementation and satisfaction of the principles of thermodynamics. This study presents the predictive capabilities of three different forms of viscous potential functions over five soft materials, including polyvinyl alcohol hydrogel, optically clear adhesive, elastomeric polyurethane, very high bond 4910, and styrene-ethylene-butylene-styrene gel. Accuracy of the predictions was quantified using the coefficient of determination and the normalized mean absolute difference. Results demonstrated that a recently proposed viscous potential function, named model 3 in this study, is relatively accurate and versatile in describing the rate-dependent behavior of soft materials. The results presented herein help researchers and design engineers to select the right models, provide insights into existing limitations, and guide the development of improved and more versatile models.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105547"},"PeriodicalIF":4.1,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grain Boundaries (GBs) disrupt the motion of dislocations and thereby affect the elasto-plastic deformation behavior of polycrystalline alloys. A majority of conventional polycrystal plasticity models represent GBs as sharp interfaces and do not incorporate GB micro-mechanics. In this work, a novel constitutive formulation for finitely thick GB region is developed which incorporates properties of all the adjoining grains. The GB model is based on penalizing the slip rate on the slip systems of single crystals in the GB region with an extra activation energy term. The energy penalty is based on minimizing the remnant dislocation line on GB for incoming and outgoing slip systems and evolves with slip accumulation. The size dependent elasto-plastic response of polycrystals is captured in this model by incorporating Geometrically Necessary Dislocations (GNDs) in addition to the Statistically Stored Dislocations (SSDs). The model has been implemented in a Crystal Plasticity Finite Element Method (CPFEM) code and applied to simulate the plane strain uni-axial tensile deformation of FCC polycrystals. The analyses show that the model is able to capture: (i) the single crystal response for a bicrystal with zero misorientation; and (ii) the dependence of Hall–Petch factor on misorientation. A normalized critical GB thickness value has also been derived which renders the macroscopic response insensitive to the GB region size. Polycrystal CPFEM simulations demonstrate that the model can capture the strain dependence of Hall–Petch factor reasonably well.
{"title":"A grain boundary region model to capture grain size and misorientation effects on elasto-plastic response of polycrystals","authors":"Devesh Tiwari , Ayub Khan , Pierre-Antony Deschênes , Daniel Paquet , Pritam Chakraborty","doi":"10.1016/j.mechmat.2025.105541","DOIUrl":"10.1016/j.mechmat.2025.105541","url":null,"abstract":"<div><div>Grain Boundaries (GBs) disrupt the motion of dislocations and thereby affect the elasto-plastic deformation behavior of polycrystalline alloys. A majority of conventional polycrystal plasticity models represent GBs as sharp interfaces and do not incorporate GB micro-mechanics. In this work, a novel constitutive formulation for finitely thick GB region is developed which incorporates properties of all the adjoining grains. The GB model is based on penalizing the slip rate on the slip systems of single crystals in the GB region with an extra activation energy term. The energy penalty is based on minimizing the remnant dislocation line on GB for incoming and outgoing slip systems and evolves with slip accumulation. The size dependent elasto-plastic response of polycrystals is captured in this model by incorporating Geometrically Necessary Dislocations (GNDs) in addition to the Statistically Stored Dislocations (SSDs). The model has been implemented in a Crystal Plasticity Finite Element Method (CPFEM) code and applied to simulate the plane strain uni-axial tensile deformation of FCC polycrystals. The analyses show that the model is able to capture: (i) the single crystal response for a bicrystal with zero misorientation; and (ii) the dependence of Hall–Petch factor on misorientation. A normalized critical GB thickness value has also been derived which renders the macroscopic response insensitive to the GB region size. Polycrystal CPFEM simulations demonstrate that the model can capture the strain dependence of Hall–Petch factor reasonably well.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105541"},"PeriodicalIF":4.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1016/j.mechmat.2025.105544
Suraj Ravindran , Addis Kidane
This study presents a multiscale experimental investigation and characterization of the formation and propagation of compaction waves in an energetic material simulant, polymer-bonded sugar (PBS), under impact loading. Local and macroscale deformation measurements during loading were performed using ultrahigh-speed photography combined with digital image correlation (DIC). The compaction wave velocity and propagation parameters were calculated from macroscale experiment data. A weak-shock-type compaction profile with a smooth front was observed at intermediate impact velocities. After a brief period of relatively stable compaction propagation, the wavefront was observed to widen as it propagated. Mesoscale measurements revealed a rough compaction front resulting from the formation of force chains, local viscous flow of the binder, and crystal fracture. The widening of the compaction wave is attributed to energy dissipation caused by viscous binder flow and local crystal fracture. Crystal fractures occurred at relatively low average stress levels and were associated with the formation of force chains. Finally, the effects of impact velocity and volume fraction on local deformation mechanisms during compaction wave formation are discussed.
{"title":"Multiscale compaction behavior of granular composites","authors":"Suraj Ravindran , Addis Kidane","doi":"10.1016/j.mechmat.2025.105544","DOIUrl":"10.1016/j.mechmat.2025.105544","url":null,"abstract":"<div><div>This study presents a multiscale experimental investigation and characterization of the formation and propagation of compaction waves in an energetic material simulant, polymer-bonded sugar (PBS), under impact loading. Local and macroscale deformation measurements during loading were performed using ultrahigh-speed photography combined with digital image correlation (DIC). The compaction wave velocity and propagation parameters were calculated from macroscale experiment data. A weak-shock-type compaction profile with a smooth front was observed at intermediate impact velocities. After a brief period of relatively stable compaction propagation, the wavefront was observed to widen as it propagated. Mesoscale measurements revealed a rough compaction front resulting from the formation of force chains, local viscous flow of the binder, and crystal fracture. The widening of the compaction wave is attributed to energy dissipation caused by viscous binder flow and local crystal fracture. Crystal fractures occurred at relatively low average stress levels and were associated with the formation of force chains. Finally, the effects of impact velocity and volume fraction on local deformation mechanisms during compaction wave formation are discussed.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105544"},"PeriodicalIF":4.1,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1016/j.mechmat.2025.105545
Huixin Wei , Wei Fang , Shibin Wang , Zhiyong Wang , Zehui Lin , Baopeng Liao
Understanding the friction behavior of soft materials critically depends on the precise characterization of the contact interface. The current characterization methods of friction behavior are limited by its predominant reliance on data from the sliding stage, which often neglects the static friction. In this study, a friction model describing the static friction stage of soft materials is proposed, considering contact deformation and stick slip phenomena. A tribometry platform is designed to investigate these interfacial phenomena during soft material friction. The platform integrates an optical visualization setup with high-resolution imaging components and mechanical loading systems, enabling real-time monitoring of contact evolution. An automated image processing algorithm with edge detection is developed to quantitatively extract displacement-dependent contact zone boundaries from the captured image sequences. Full-field displacement mapping within the contact zone is achieved through integration with two-dimensional digital image correlation (2D-DIC) analysis. The friction coefficient can be further determined by friction model and stick-slip data in static friction. The developed methodology provides new insights into interfacial mechanisms and a characterization framework for sliding friction of soft material, with the applicability in evaluating grip performance of robotics.
{"title":"Characterizing friction coefficients of soft materials via stick-slip data in static friction: Mechanism analysis and experimental validation","authors":"Huixin Wei , Wei Fang , Shibin Wang , Zhiyong Wang , Zehui Lin , Baopeng Liao","doi":"10.1016/j.mechmat.2025.105545","DOIUrl":"10.1016/j.mechmat.2025.105545","url":null,"abstract":"<div><div>Understanding the friction behavior of soft materials critically depends on the precise characterization of the contact interface. The current characterization methods of friction behavior are limited by its predominant reliance on data from the sliding stage, which often neglects the static friction. In this study, a friction model describing the static friction stage of soft materials is proposed, considering contact deformation and stick slip phenomena. A tribometry platform is designed to investigate these interfacial phenomena during soft material friction. The platform integrates an optical visualization setup with high-resolution imaging components and mechanical loading systems, enabling real-time monitoring of contact evolution. An automated image processing algorithm with edge detection is developed to quantitatively extract displacement-dependent contact zone boundaries from the captured image sequences. Full-field displacement mapping within the contact zone is achieved through integration with two-dimensional digital image correlation (2D-DIC) analysis. The friction coefficient can be further determined by friction model and stick-slip data in static friction. The developed methodology provides new insights into interfacial mechanisms and a characterization framework for sliding friction of soft material, with the applicability in evaluating grip performance of robotics.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"213 ","pages":"Article 105545"},"PeriodicalIF":4.1,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-08DOI: 10.1016/j.mechmat.2025.105540
Shengduo Liu, Kaushik Bhattacharya, Nadia Lapusta
Empirical rate-and-state friction laws are widely used in geophysics and engineering to simulate interface slip. They postulate that the friction coefficient depends on the local slip rate and a state variable that reflects the history of slip. Depending on the parameters, rate-and-state friction can be either rate-strengthening, leading to steady slip, or rate-weakening, leading to unsteady stick–slip behavior modeling earthquakes. Rate-and-state friction does not have a potential or variational formulation, making implicit solution approaches difficult and implementation numerically expensive. In this work, we propose a potential formulation for the rate-and-state friction. We formulate the potentials as neural operators and train them so that the resulting behavior emulates the empirical rate-and-state friction. We show that this potential formulation enables implicit time discretization leading to efficient numerical implementation.
{"title":"Learning a potential formulation for rate-and-state friction","authors":"Shengduo Liu, Kaushik Bhattacharya, Nadia Lapusta","doi":"10.1016/j.mechmat.2025.105540","DOIUrl":"10.1016/j.mechmat.2025.105540","url":null,"abstract":"<div><div>Empirical rate-and-state friction laws are widely used in geophysics and engineering to simulate interface slip. They postulate that the friction coefficient depends on the local slip rate and a state variable that reflects the history of slip. Depending on the parameters, rate-and-state friction can be either rate-strengthening, leading to steady slip, or rate-weakening, leading to unsteady stick–slip behavior modeling earthquakes. Rate-and-state friction does not have a potential or variational formulation, making implicit solution approaches difficult and implementation numerically expensive. In this work, we propose a potential formulation for the rate-and-state friction. We formulate the potentials as neural operators and train them so that the resulting behavior emulates the empirical rate-and-state friction. We show that this potential formulation enables implicit time discretization leading to efficient numerical implementation.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"212 ","pages":"Article 105540"},"PeriodicalIF":4.1,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.mechmat.2025.105543
Dianyin Hu , Tao Wang , Hongyang Huang , Jianxing Mao , Jier Wang , Xin Wang , Yang Gao , Liucheng Zhou , Rongqiao Wang
Residual stress relaxation phenomena under thermomechanical conditions, particularly thermal exposure and cyclic loading, constitute critical determinants of fatigue performance in surface-treated engineering components. This study systematically investigates the thermal and cyclic relaxation mechanisms in shot-peened Ni-based superalloy GH4720Li through integrated experimental characterization and computational modeling. Through systematic characterization via X-ray diffraction (XRD) and electron backscatter diffraction (EBSD), we establish quantitative correlations between residual stress relaxation kinetics and concurrent microstructure evolution, particularly dislocation annihilation and grain boundary restructuring. Building upon these observations, a novel multilayer constitutive framework is developed to decouple the synergistic effects of microstructural evolution on residual stress relaxation dynamics. The model demonstrates predictive accuracy within 6.3 % for residual stress magnitudes and 3.3 % for characteristic depth parameters when compared to stabilized thermal exposure data. Under cyclic loading conditions, corresponding errors remain constrained to 15.5 % and 4.8 %, respectively. Such precision validates the model's capability to isolate microstructure-driven relaxation mechanisms from purely mechanical contributions. This multi-physics framework provides an unprecedented quantitative tool for optimizing surface-engineered components operating in combined high-temperature and cyclic loading environments, effectively bridging the gap between microstructure-aware modeling and industrial fatigue life prediction.
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