Mechanics of Materials最新文献

{"title":"The effect of microstructural inertia on plastic localization and void growth in porous solids","authors":"N. Hosseini ,&nbsp;T. Virazels ,&nbsp;N. Jacques ,&nbsp;J.A. Rodríguez-Martínez","doi":"10.1016/j.mechmat.2025.105339","DOIUrl":"10.1016/j.mechmat.2025.105339","url":null,"abstract":"<div><div>This paper investigates the impact of microinertia on plastic localization, void growth, and coalescence in ductile porous materials subjected to high strain rates. For that purpose, we have performed finite element calculations on a flat double-notched specimen subjected to dynamic plane strain tension. The simulations employ three distinct approaches to model the mechanical behavior of the porous aggregate: (1) discrete voids within a matrix material governed by von Mises plasticity; (2) homogenized porosity represented using standard quasi-static Gurson–Tvergaard plasticity; and (3) homogenized porosity described with Gurson–Tvergaard plasticity extended by Molinari and Mercier (2001) to account for microinertia effects. The porous microstructures used in the simulations are representative of additive manufactured metals, featuring initial void volume fractions varying between 0.5% and 4%, and pore diameters ranging from <span><math><mrow><mn>30</mn><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span> to <span><math><mrow><mn>150</mn><mspace></mspace><mi>μ</mi><mtext>m</mtext></mrow></math></span> (Marvi-Mashhadi et al., 2021, Nieto-Fuentes et al., 2023). The applied tensile velocities ranged from <span><math><mrow><mn>100</mn><mspace></mspace><mtext>m</mtext><mo>/</mo><mtext>s</mtext></mrow></math></span> to <span><math><mrow><mn>1000</mn><mspace></mspace><mtext>m</mtext><mo>/</mo><mtext>s</mtext></mrow></math></span>, producing strain rates between <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> and <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>6</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, and stress triaxiality values spanning from 4 to 30. The simulations with discrete voids validate the calculations performed using homogenized porosity and microinertia effects, demonstrating that higher strain rates and larger pore sizes lead to slower void growth and a delayed, regularized plastic localization. Conversely, the standard Gurson–Tvergaard model shows notable mesh sensitivity and fails to describe the influence of the loading rate on plastic localization. Ultimately, the comparison between finite element models with discrete voids and those with homogenized porosity illustrates the stabilizing effects of porous microstructure and multiscale inertia on dynamic plastic flow, while also highlighting the strengths of the constitutive model introduced by Molinari and Mercier (2001) for simulating engineering problems involving porous ductile materials subjected to high-velocity impacts.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105339"},"PeriodicalIF":3.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863483","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}

{"title":"On modeling fracture of soft polymers","authors":"Aditya Konale ,&nbsp;Vikas Srivastava","doi":"10.1016/j.mechmat.2025.105346","DOIUrl":"10.1016/j.mechmat.2025.105346","url":null,"abstract":"<div><div>Soft polymers are ubiquitous materials in nature and as engineering materials with properties varying from rate-independent to rate-dependent. Current fracture toughness measures are non-unique for rate-dependent soft materials for varying loading profiles and specimen geometries. Works on modeling fracture in rate-dependent soft polymers are limited to specific pre-cracked geometries. There is no generally agreed-upon model for the fracture of soft polymers. We propose and show that a critical value of stress work can be used as a measure of fracture resistance in soft polymers. We develop a damage model to predict fracture in soft polymers. In the model, the energetic part of the critical stress work is proposed as a damage initiation criterion that has the ability to capture failure surfaces. The damage growth is modeled through a generalized gradient-damage framework. The fracture model is validated for both elastomers and viscous soft polymers by comparing model predictions against experimental results for different materials (ethylene propylene diene monomer — EPDM, EPS25 vitrimer, styrene butadiene rubber — SBR, and polyborosiloxane — PBS), a variety of specimen geometries, and loading conditions. The model can predict key physical phenomena such as brittle and ductile responses and different fracture profiles. The microstructural quantities, such as subchain dissociation energy during the fracture of polymers, can be predicted from the macroscopic model parameters.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105346"},"PeriodicalIF":3.4,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916626","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}

{"title":"Plane waves in nonlocal elastic–plastic materials containing voids","authors":"Suraj Kumar ,&nbsp;S.K. Tomar","doi":"10.1016/j.mechmat.2025.105344","DOIUrl":"10.1016/j.mechmat.2025.105344","url":null,"abstract":"<div><div>Constitutive relations and dynamical equations are derived for nonlocal elastic–plastic solid materials containing voids. The plastic effect is considered through the dislocation of planes from their original position during the deformation process. Four plane waves with distinct speeds are found to travel in the considered medium of infinite extent comprising of three sets of coupled elastic–plastic waves and a lone transverse wave. Each set of the coupled elastic–plastic waves is found to be influenced by nonlocality, plasticity and voids present in the medium. While the lone transverse wave is found to be influenced by the nonlocality only and remains independent of the presence of plasticity and voids in the medium. One of the sets of coupled elastic–plastic waves disappears in the absence of plasticity from the medium. Numerical computations are performed for a particular model to understand the propagation characteristics of the existed waves. The effects of various parameters are noticed on the propagation characteristics, depicted graphically and explained.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105344"},"PeriodicalIF":3.4,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143843381","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}

{"title":"Supershear cracks appear along weak interface in semi-regular lattices under pre-tension","authors":"Yuheng Liu ,&nbsp;Xing Yang ,&nbsp;Bin Zhang","doi":"10.1016/j.mechmat.2025.105347","DOIUrl":"10.1016/j.mechmat.2025.105347","url":null,"abstract":"<div><div>Rapid fracture of three semi-regular lattices (kagome, snub-square, elongated-triangular) is studied with pre-stretched strip models of finite element. Considering inherent geometric nonlinearity, the dynamic crack propagation is triggered by suddenly introducing an edge crack along the middle weak interface. We observed that the speed of mode I crack exceeds the shear wave speed of lattices, and tensile crack in the kagome lattice even travels faster than the pressure wave, which shatters the prediction of classical fracture theory. Pre-stretch level dominates the supershear fracture of lattices. As the pre-strain exceeds the critical value of lattice geometry, supershear propagation occurs, which is confirmed by theoretical prediction of the crack speed in lattices. As the crack speed increases further, the oblique shear shock front and pressure shock front form around the crack tip. Moreover, the energy near the crack tip flows toward the crack wake to form shock wave fronts. This study may deepen the understanding of supershear fracture in lattice metamaterials.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105347"},"PeriodicalIF":3.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143790801","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}

{"title":"Impact of position and density of nanoscale voids on fracture initiation in iron from phase field fracture simulation","authors":"An T. Ta ,&nbsp;Yixi Shen ,&nbsp;R. Seaton Ullberg ,&nbsp;Michael R. Tonks ,&nbsp;Simon R. Phillpot ,&nbsp;Douglas E. Spearot","doi":"10.1016/j.mechmat.2025.105348","DOIUrl":"10.1016/j.mechmat.2025.105348","url":null,"abstract":"<div><div>Understanding the impact of helium bubbles on crack propagation is complex. A useful first study towards understanding bubble effects on fracture is to examine how voids impact fracture. In this work, we used phase-field fracture simulations to examine the influence of voids and their distribution on Mode I fracture in Fe. Assuming brittle fracture, two simulation configurations were considered: (1) nanoscale systems with one or two voids, and (2) nanoscale systems with an experimentally relevant distribution of voids, with up to 20 % void area. Results from simulations with one and two voids showed that voids within 10 nm of a crack tip reduce the stress required for crack growth, with the magnitude of reduction depending on void-to-crack orientation. Comparisons with linear elastic fracture mechanics and evaluation of one versus two void systems revealed deviations from linear superposition, implying complex interactions between void and crack tip stress fields. In multi-void simulations, as void sizes increase, the nearest void to the crack tip exerts a greater influence on fracture stress than the overall porosity. This study provides valuable insights into the relationship between void size and concentration, and the stress necessary for crack growth, marking a step forward towards understanding He bubble-induced fracture in ferrous materials.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105348"},"PeriodicalIF":3.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143815615","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}

{"title":"Crystallization-induced residual deformation evolution in thermoplastics during material extrusion and subsequent annealing","authors":"Shuailong Ren ,&nbsp;Zhihong Han ,&nbsp;Yulin Xiong ,&nbsp;Hongqiu Wei ,&nbsp;Jinyou Xiao ,&nbsp;Lihua Wen ,&nbsp;Ming Lei ,&nbsp;Xiao Hou","doi":"10.1016/j.mechmat.2025.105345","DOIUrl":"10.1016/j.mechmat.2025.105345","url":null,"abstract":"<div><div>Thermomechanical histories in material extrusion (MEX) and subsequent high-temperature service strongly influence the geometric accuracy of semi-crystalline thermoplastic structures. The crystallization-induced residual stress generated in MEX manufacturing process is partially released during subsequent annealing at moderate temperatures. However, high-temperature annealing induces further cold crystallization and additional residual deformation. Therefore, releasing and generating of residual stress in subsequent annealing would affect the high-temperature performance of structural components made by MEX. Tracing the crystallization history during manufacturing and subsequent annealing plays a key role in design and evaluation of components made by MEX throughout the entire lifecycle. To address this issue, we developed a process simulation method for MEX based on the element activation technology of the finite element method and a continuous phase evolution constitutive model of thermoplastic crystallization. In the simulation, the elements of the target object are sequentially activated following the real manufacturing path, and the thermomechanical boundary conditions are updated stepwise. In the constitutive model, crystal growth is modeled by a series of continuously formed crystal phases that are sequentially added to the initial amorphous medium to memorize the crystallization history coupled with the entire deformation history. Therefore, during subsequent annealing, the crystallization-induced bi-directional bending of the polylactic acid frame structure is observed in the simulation, and then verified by experiments. The square frame structure after MEX is observed first to bend downward and finally to bend upward during subsequent annealing. The initial downward bending is induced by the release of the residual stress generated by crystallization during MEX manufacturing, and the final upward bending is induced by the orientation difference of the crystals formed during manufacturing and subsequent annealing. Overall, the good agreement indicates that the developed method can accurately describe the inheritance of the crystalline state during manufacturing on the subsequent high-temperature service performance.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105345"},"PeriodicalIF":3.4,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143790803","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}

{"title":"Influence of the shape of cohesive zone models on the peeling of stiff film/soft substrate systems: A theoretical perspective","authors":"Hao Long ,&nbsp;Yanwei Liu ,&nbsp;Hanbin Yin ,&nbsp;Yueguang Wei","doi":"10.1016/j.mechmat.2025.105343","DOIUrl":"10.1016/j.mechmat.2025.105343","url":null,"abstract":"<div><div>Peel tests have been widely used to measure the interfacial properties of thin film/substrate systems. With the emergence of soft materials and structures, there is a growing need to characterize the interface of stiff film/soft substrate systems. The accurate prediction of their peeling behaviors relies on cohesive zone models (CZMs), but the influence of the shape of CZMs remains unclear. Herein, we propose a theoretical model based on the trapezoidal CZM to characterize the 90-degree peeling of stiff film/soft substrate systems, and this model can degenerate into those based on Dugdale’s and bilinear CZMs. We validate the theoretical solutions for different shapes of CZMs by finite element simulations, and reveal that the maximum peeling force (<span><math><mrow><msub><mi>P</mi><mi>max</mi></msub></mrow></math></span>) and the corresponding cohesive zone length (<span><math><mrow><msubsup><mi>l</mi><mtext>CZ</mtext><mi>max</mi></msubsup></mrow></math></span>) are significantly affected by the shape of CZMs. We further obtain the unified power scaling laws of <span><math><mrow><msub><mi>P</mi><mi>max</mi></msub></mrow></math></span> and <span><math><mrow><msubsup><mi>l</mi><mtext>CZ</mtext><mi>max</mi></msubsup></mrow></math></span> for different shapes of CZMs, where the scaling exponents depend on substrate elasticity and the shape of CZMs. By a simple extension of the present model, we find that the presence of a small initial interfacial crack can lead to a significant decrease of <span><math><mrow><msub><mi>P</mi><mi>max</mi></msub></mrow></math></span>. When the initial interfacial crack is long, the influences of the substrate modulus, the shape of CZMs and the interfacial strength on <span><math><mrow><msub><mi>P</mi><mi>max</mi></msub></mrow></math></span> can be ignored, and the peeling is governed by the interfacial fracture energy. With the present theoretical solutions, the interfacial strength and fracture energy of stiff film/soft substrate systems can be extracted simultaneously via 90-degree peel tests as long as the shape of CZMs is given and the initial interfacial crack is not very long. We expect that the present model can be extended to the case of arbitrary multi-linear CZMs, which can approximate arbitrarily shaped CZMs. These results can help us measure the interfacial properties of stiff film/soft substrate systems via peel tests, and understand the influence of the shape of CZMs on the interfacial fracture from a theoretical perspective.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105343"},"PeriodicalIF":3.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747916","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}

{"title":"Thermo-mechanical modeling and behavior analysis of titanium-matrix composites via laser powder bed fusion","authors":"Yang Yang ,&nbsp;Zhi-Jian Li ,&nbsp;Yuan Yao ,&nbsp;Hong-Liang Dai","doi":"10.1016/j.mechmat.2025.105342","DOIUrl":"10.1016/j.mechmat.2025.105342","url":null,"abstract":"<div><div>Laser powder bed fusion (LPBF) gives new insights into the effective fabrication of multi-material parts. However, they have not reached mechanical reliability due to undesirable physical defects such as porosity related to powder spatter. The effect of a powder bed-substrate system with such defects on the thermo-mechanical behavior of multi-material parts is still unclear. In this paper, considering porosity due to powder spatter, a multi-material property model of titanium-matrix composites (TMCs) is established based on the mixture method. Considering temperature-dependent thermal properties, an integrated thermo-mechanical modeling of TMCs is developed to predict the residual stress and deformation of the as-built parts. The three-dimensional transient thermal and stress fields are predicted using the differential quadrature method (DQM). The predicted results show excellent agreement with the predictions and experimental results in the literature. Furthermore, the effect of process parameters, ceramic, part dimension, and porosity on the thermo-mechanical responses of TMCs is analyzed. The results show that the interface between the powder bed and substrate is subjected to the highest thermal gradient and residual stress. In addition, the thermal gradient, residual stress, and interfacial deformation increase with the increased energy density, porosity, and substrate thickness. These results can provide a guide for the design and manufacturing of multi-material parts via LPBF.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105342"},"PeriodicalIF":3.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761145","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}

{"title":"A constitutive model of temperature gradient driving diffusion in solids with stress effect","authors":"Feng Xie,&nbsp;Xin Xu,&nbsp;Weixu Zhang","doi":"10.1016/j.mechmat.2025.105340","DOIUrl":"10.1016/j.mechmat.2025.105340","url":null,"abstract":"<div><div>In the presence of temperature gradient, the non-uniform redistribution of solute atom usually occurs in an initially uniform solid, e.g. the segregation of alloy element in the gas turbine blade, and this phenomenon is called as Ludwig-Soret effect. The redistribution process of solute atom accompanies a significant stress in solids, which was not taken into account in previous theories. In this paper, in the framework of the irreversible thermodynamics, we establish a constitutive model of temperature gradient driving diffusion. The redistribution process of solute atom and the effect of stress are investigated, respectively. The results reveal that our established model describes the redistribution law of solute atom and clarifies the implied mechanism. And the redistribution of solute atom firstly starts at the hot end and gradually extends towards the cold end. Stress retards the diffusion driven by the temperature gradient and then reduces the non-uniform redistribution of solute atom. Moreover, the obtained quantitative relationship predicts the direction and magnitude of the formed concentration gradient. According to our results, researchers can optimize the distribution of element and evaluate the service performance of engineering materials.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105340"},"PeriodicalIF":3.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143790802","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}

{"title":"Quantitatively predicting and evaluating the hardness of amorphous ribbons via a deep learning-symbolic regression approach","authors":"Bo Pang ,&nbsp;Zhilin Long ,&nbsp;Tao Long ,&nbsp;Zhonghuan Su","doi":"10.1016/j.mechmat.2025.105341","DOIUrl":"10.1016/j.mechmat.2025.105341","url":null,"abstract":"<div><div>Amorphous ribbons are applicable across various fields due to their advantageous mechanical, physical, and electromagnetic properties. One such property, Vickers hardness (<em>H</em>_v), is foundational and intimately linked with other properties, which have attracted a growing amount of attention from researchers. However, there is a paucity of a well-performed expression for amorphous ribbons that could quantitatively guide the design of new ones with the desired <em>H</em>_v. In the present study, nine machine learning (ML) algorithms were executed on a dataset previously collected by the authors. By comparing the coefficients of determination (<em>R</em>²) of these algorithms on the test sets, the descriptor ranking of the model with the highest accuracy was obtained. Then, the final expression was successfully explored by utilizing three key descriptors, which was accomplished by synthesizing the <em>R</em>² values, descriptor ranking, and Pearson Correlation Coefficient (PCC) for different feature subsets. Furthermore, the intricate relationship between these features and <em>H</em>_v was elucidated during exploration. The efficacy of this framework may also offer insights into the discovery of other properties of novel amorphous ribbons.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"206 ","pages":"Article 105341"},"PeriodicalIF":3.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823953","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}