Mechanics of Materials最新文献

{"title":"Ab initio calculation of surface elasticity parameters in cubic crystalline films with surface point defects: Effects on SH wave propagation","authors":"P. Behnoud ,&nbsp;H.M. Shodja","doi":"10.1016/j.mechmat.2025.105366","DOIUrl":"10.1016/j.mechmat.2025.105366","url":null,"abstract":"<div><div>Elastic material surface and interface properties have non-negligible influences on the behavior of nano-sized elastic objects. Even though the concern and the need for the evaluation of surface properties were raised in 1876 by Gibbs, due to serious experimental and theoretical difficulties their measurements have remained idle till only recently. This paper offers a theoretical approach for an accurate evaluation of free surface energy density, surface layer relaxation, surface elastic constants, surface residual stresses, and surface mass density for the (100) and (111) planes of several non-magnetic cubic metals. Moreover, the analysis is extended to the surfaces where point defects, such as vacancies and substitutional impurity atoms, are present. The interaction of these point defects with surface is in particular important for irradiation and fracture phenomena. The present results are compared with the recent available experimental and theoretical data. For the sake of illustration of the importance of surface effects, the propagation of horizontally polarized shear waves (SH waves) in ultra-thin layers of only a few lattice parameters height will be studied. Utilizing the theoretically calculated surface parameters herein, the surface effects with and without the above-mentioned surface point defects will be examined in some details. Thus, the negative dispersion of SH waves within surface elasticity theory will be showcased quantitatively for various cubic crystals of interest. Moreover, the effects of the crystallographic orientations will also be examined in the presence and absence of surface point defects.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105366"},"PeriodicalIF":3.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169284","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":"Role of crystal orientations and loading conditions on the microstructure evolution and void evolution dynamics in single crystal iron: An atomistic investigation","authors":"Sunil Rawat ,&nbsp;Vinay Rastogi","doi":"10.1016/j.mechmat.2025.105387","DOIUrl":"10.1016/j.mechmat.2025.105387","url":null,"abstract":"<div><div>An understanding of void evolution dynamics is required to develop/improve fracture models at a high strain rate to predict spall fracture at the macroscale. We perform molecular dynamics simulations to explore the role of crystal orientations and loading conditions on the microstructure evolution and void evolution dynamics in single-crystal iron. We find that all the cases of crystal orientations show structural transformations consistent with experiments. The dominance of the nucleation and growth of voids is sensitive to the applied loading conditions and crystal orientations. Void growth dominates under uniaxial deformation, and void nucleation dominates under triaxial deformation. Peak tensile pressure, the amount of structural transformation, and overall void volume fraction are insensitive to the crystal orientations under triaxial deformation, while they are susceptible under uniaxial and biaxial deformations. The dislocation evolution, number of voids, and size distributions of voids are all very sensitive to the applied loading conditions and crystal orientations. A small percentage of voids accounts for the majority of the total volume of the voids.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105387"},"PeriodicalIF":3.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169453","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-the-fly adaptive sampling strategy for data-driven computational mechanics: Applications to computational homogenisation","authors":"Felipe Rocha ,&nbsp;Auriane Platzer ,&nbsp;Adrien Leygue ,&nbsp;Laurent Stainier","doi":"10.1016/j.mechmat.2025.105382","DOIUrl":"10.1016/j.mechmat.2025.105382","url":null,"abstract":"<div><div>To overcome well-known drawbacks of classical phenomenological constitutive modelling of non-linear heterogeneous materials, a popular approach is the so-called computational homogenisation (CH), which relies on a combined description of constitutive behaviours and spatial morphology of smaller scales constituents. Their computational implementation usually encompasses two-level finite element numerical models (FE<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>), which quickly leads to prohibitive computational costs, even for problems with a modest number of degrees of freedom. A popular strategy in the literature to alleviate such computational burden is to use machine learning-based surrogate constitutive models, although fundamental drawbacks such as the absence of interpretability, limited extrapolation capability, and limited mathematical analysis, are still present. On the other hand, the so-called (model-free) data-driven computational mechanics (DDCM) paradigm Kirchdoerfer and Ortiz (2016) proposes the direct integration of “experimental data”, completely bypassing the need for explicit constitutive laws. The main goal of this work is to show how the DDCM approach can be used in synergy with CH to bypass fully-coupled multiscale computations. A naive approach to using multiscale constitutive behaviour along with DDCM is the offline construction of a database via CH by assuming some sampling of the strain-space. This approach has little interest since the region of the strain-space covered during a simulation is problem-dependent. During the iterations of the DDCM solver, a finite set of strain–stress pairs is used as input, while another set, comprising mechanically admissible states, is dynamically generated. Such a scenario naturally unveils the most relevant goal-oriented phase-space instances to guide a material dataset enrichment iterative procedure, bridging DDCM and CH towards computationally effective two-scale simulations. On the other hand, the performance is limited if the quality of the mechanically admissible states is low, particularly when the material dataset is not insufficiently dense. To address these challenges, we propose meaningful ranking scores alongside numerical techniques to enhance the DDCM solver in sparse data scenarios. As result, we show through meaningful numerical examples that the proposed framework results in significant computational savings if compared to standard FE<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105382"},"PeriodicalIF":3.4,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169465","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":"Exploration of digital volume correlation in nominally homogeneous metals","authors":"K. Jose,&nbsp;Z. Meng,&nbsp;A.R. Dennis,&nbsp;I. Grega,&nbsp;A.J.D. Shaikeea,&nbsp;V.S. Deshpande","doi":"10.1016/j.mechmat.2025.105394","DOIUrl":"10.1016/j.mechmat.2025.105394","url":null,"abstract":"<div><div>The ability to conduct digital volume correlation (DVC) in nominally homogeneous metals using X-ray computed tomography (XCT) is examined by a combination of synthetic and experimental techniques. DVC requires markers to track within the volume and we first discuss methods by which the grayscale variations due to inherent inhomogeneities in nominally homogeneous metals can be enhanced in X-ray scans. Using these enhanced scans we then validate the predictions of the DVC algorithm via a combination of synthetically imposed rigid motions and complex displacement fields. The rigid body motions are captured very easily as the fields are dominated by motion of the specimen boundaries where a high grayscale contrast exists between the metal and air. The local deformation fields where there is no boundary motion require high quality tomographic scans, and we explore the range of hyperparameters that give high fidelity predictions. The study is then extended to real displacement fields obtained from experiments. A key conclusion is that hyperparameters optimised by imposing synthetic displacement fields are often inappropriate. This is because the changes to the image grayscales that occur due to the actual deformation of metals are different from those assumed in the algorithms used to impose synthetic deformations. Using a combination of different specimen geometries and known physical behaviour of the specimens, we reoptimise the hyperparameters in a global DVC algorithm that naturally uses boundary information. Finally, we also explore “hardware” methods to improve the DVC predictions. Our results show promise and suggest routes for further improvements.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105394"},"PeriodicalIF":3.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139025","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":"Mechanistic study on mechanical properties of graphene origami/aluminum nanocomposites under nanoindentation","authors":"Xinxiu Yu ,&nbsp;Duosheng Li ,&nbsp;Qing H. Qin ,&nbsp;Yin Ye ,&nbsp;Zhiguo Ye ,&nbsp;Feng Xu ,&nbsp;Wenzhuang Lu","doi":"10.1016/j.mechmat.2025.105381","DOIUrl":"10.1016/j.mechmat.2025.105381","url":null,"abstract":"<div><div>Nano-phase (graphene)/Al matrix composites exhibit a trade-off between strength and toughness. In this study, we present a novel approach to achieving synergistic effect between strength and toughness by constructing graphene origami/aluminum nanocomposites (GOri/Al). Molecular dynamics (MD) simulations were applied to investigate the nanoindentation behavior and reveal the strengthening and toughening mechanisms of the GOri/Al. The results show that compared to graphene/aluminum composites (Gra/Al), GOri/Al exhibits a 35 % enhancement in fracture toughness and a 22 % improvement in load-bearing capacity respectively. In the Gra/Al, the graphene fails and fractures at an indentation depth of 49.8 Å, resulting in the loss of reinforcement. In contrast, the GOri in the GOri/Al remains intact at an indentation depth of 55 Å with a unique unfolding process. After the indenter is completely unloaded, the GOri/Al shows significantly reduced dislocations and excellent plastic recovery. In the elastic stage, the speed of dislocation nucleation in different systems is the main factor affecting the indentation force. When the diamond indenter begins to interact with the insertion layer, the C-C bond stretching tension in the graphene causes a significant increase in indentation force, while the GOri is still in its buffering phase. In the plastic stage, stress in the GOri/Al is distributed along the periphery, with the ridges of the folds bearing more stress, effectively relieving stress concentrations. Adding a GOri together with a graphene of the same size to the Al further enhances the composite flexibility, strength, and hardness. Finally, the effects of indenter speed and indenter radius on the mechanical properties of the GOri/Al are also investigated. Our study provides a novel theoretical analysis and approach for the development of new Al nanocomposites.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105381"},"PeriodicalIF":3.4,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116242","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-the-fly meanfield transition-state theory for diffusive molecular dynamics","authors":"M. Molinos ,&nbsp;M. Ortiz ,&nbsp;M.P. Ariza","doi":"10.1016/j.mechmat.2025.105380","DOIUrl":"10.1016/j.mechmat.2025.105380","url":null,"abstract":"<div><div>We apply transition state theory to derive atomic-level master equations for mass transport from empirical interatomic potentials within the Diffusive Molecular Dynamics (DMD) framework. We show that meanfield approximation provides an exceedingly efficient and accurate means of computing free-energy barriers in arbitrary local atomic configurations, thus enabling long-term DMD ‘on-the-fly’ and on the sole basis of an underlying interatomic potential, without additional modeling assumptions. We apply and validate the resulting meanfield DMD paradigm in simulations of processes of hydrogenation and dehydrogenation of Mg using Angular-Dependent interatomic Potentials (ADP). We show that meanfield DMD correctly predicts hydrogen diffusivities in hcp Mg and vacancy diffusivities in rutile <span><math><msub><mrow><mi>MgH</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. We demonstrate the ability of meanfield DMD to predict evolution through calculations concerned with dilute concentrations of hydrogen in hcp Mg, and with dilute concentrations of hydrogen vacancies in rutile <span><math><msub><mrow><mi>MgH</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>, including off-stoichiometry hydrogen concentrations and temperature effects. Remarkably, the time steps required by DMD are up to six orders of magnitude larger than those required by Molecular Dynamics (MD), which demonstrates the overwhelming superiority of the DMD paradigm in simulations of phenomena occurring on the diffusive time scale.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105380"},"PeriodicalIF":3.4,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105515","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":"Exploring forming limit of stainless steel below room temperature by Nakazima tests using an actively cooled additively manufactured punch","authors":"Konrad Barth ,&nbsp;Mohamadreza Afrasiabi ,&nbsp;Markus Bambach","doi":"10.1016/j.mechmat.2025.105392","DOIUrl":"10.1016/j.mechmat.2025.105392","url":null,"abstract":"<div><div>The hardening behavior of metastable austenitic stainless steel 1.4301, which undergoes the Transformation Induced Plasticity (TRIP) effect, is influenced by various factors, including the plastic strain, the temperature, and the current martensite content. Investigating the forming limit of this material in relation to temperature is, therefore, crucial to understand its processability and determining its range of applications. Since the forming limit curve (FLC) above room temperature has been extensively studied for this stainless steel, this paper aims to provide a comprehensive theoretical-experimental investigation of the FLC slightly below room temperature. To that end, a cooled punch was designed, and the experimental setup was defined to perform isothermal Nakazima experiments at <span><math><mrow><mn>0</mn></mrow></math></span> and <span><math><mrow><mn>20</mn><mspace></mspace><mo>°</mo><mi>C</mi></mrow></math></span> temperatures. The modified maximum force criterion (MMFC) was applied to the experiments to predict the theoretical FLC of the stainless steel. Non-isothermal Nakazima tests were used to validate the MMFC calibration. The cooled punch with confocal cooling channels performed isothermal Nakazima tests within <span><math><mrow><mi>σ</mi><mo>=</mo><mn>4</mn><mspace></mspace><mo>°</mo><mi>C</mi></mrow></math></span>. The forming limit of <span><math><mrow><mn>0</mn><mspace></mspace><mo>°</mo><mi>C</mi></mrow></math></span> was below the one of <span><math><mrow><mn>20</mn><mspace></mspace><mo>°</mo><mi>C</mi><mtext>,</mtext></mrow></math></span> and the MMFC could predict the FLC and the non-isothermal paths within an overall accuracy deviation of <span><math><mrow><mn>4</mn><mspace></mspace><mo>%</mo></mrow></math></span>. Through the present investigation, we found that the martensite transformation occurs too fast at <span><math><mrow><mn>0</mn><mspace></mspace><mo>°</mo><mi>C</mi></mrow></math></span> to prolong the forming potential.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105392"},"PeriodicalIF":3.4,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124393","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 novel analytical-empirical Eulerian method for the hyperelastic layers under punch compression","authors":"Li Yang ,&nbsp;Qinghua Zhou ,&nbsp;Pu Li ,&nbsp;Yiming Chen ,&nbsp;Qiuyun Sun ,&nbsp;Jinran Li ,&nbsp;Wanyou Yang ,&nbsp;Wei Pu","doi":"10.1016/j.mechmat.2025.105391","DOIUrl":"10.1016/j.mechmat.2025.105391","url":null,"abstract":"<div><div>Accurately and efficiently solving the nonlinear mechanical fields in large deformation problems involving hyperelastic soft layers in contact with indenters has long been a challenge in mechanics. This paper aims to propose a new analytical method for incompressible hyperelastic layers under uniform compression in plane strain conditions based on Eulerian description. Utilizing this method, explicit analytical solutions for the mechanical fields of finite-thickness hyperelastic layers under uniform compression are derived. The principles for transforming the mechanical field forms when extending the neo-Hookean model to the Mooney-Rivlin model under plane strain are outlined in this study, providing a unified solution form applicable to incompressible Rivlin-type strain energy functions. During the model validation process, a mesh-to-mesh solution mapping method was implemented to effectively improve numerical accuracy. Building on the analytical solutions for uniformly compressed layers and finite element results, the method is extended to an analytical-empirical model for hyperelastic layers compressed by a flat punch with rounded edges. This model exhibits high congruence with finite element results and allows for the direct extraction of stresses and displacements from the deformed configuration without the need for coordinate transformations, significantly enhancing computational efficiency. This research provides new insights into solving contact mechanics problems of hyperelastic materials under large deformations and offers valuable references for further studies in related fields.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105391"},"PeriodicalIF":3.4,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124353","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":"Modeling the role of microplasticity on material response under fatigue loading using a microelement plastic strain accumulation model","authors":"Bhukya Venkatesh,&nbsp;Srikanth Vedantam","doi":"10.1016/j.mechmat.2025.105377","DOIUrl":"10.1016/j.mechmat.2025.105377","url":null,"abstract":"<div><div>Fatigue failure is greatly impacted by the progressive accumulation of microplastic deformation when subjected to cyclic loading below the macroscopic yielding. This paper presents microplastic deformation and its influence on fatigue response both in low and high cycle fatigue regimes using a recently developed Microelement Plastic Strain Accumulation (MPSA) approach. The MPSA approach is based on the Jenkin–Masing model, which treats materials as a large number of linear elastic–perfectly plastic parallel microelements. This microelement model provides insights into material behavior below the macroscopic yield limit under different loading conditions, which is essential for modeling high cycle fatigue failure of materials. We evaluate the evolution of the microplastic strain, ratcheting strain, stress–strain hysteresis loops, and material degradation during cyclic loading using this model. The evolution of microplastic strain allows the model to predict high cycle fatigue. Finally, we study the strength and stiffness degradation in terms of the fraction in fatigue life.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105377"},"PeriodicalIF":3.4,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105516","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":"Instability of nanoribbons on concave substrates","authors":"Jiazhen Zhang ,&nbsp;Peijian Chen ,&nbsp;Juan Peng ,&nbsp;Hao Liu ,&nbsp;Guangjian Peng ,&nbsp;Yingying Zhang","doi":"10.1016/j.mechmat.2025.105390","DOIUrl":"10.1016/j.mechmat.2025.105390","url":null,"abstract":"<div><div>The instability of nanoribbons plays a key role in fields such as sensors, photovoltaic devices, energy storage, etc., thus attracting significant attentions of both scientific and industrial communities. However, the instability behavior of nanoribbons on non-flat substrates remains unclear, which hinders the design and development of related nanodevices. Herein, the instability behavior of nanoribbons on a concave spherical substrate is explored by molecular dynamics simulation and theoretical analysis. It is found that the length of short side of nanoribbon is the key parameter dominating critical wrinkling. The instability behavior can be well tuned through adopting suitable length of short side, substrate's radius and adhesion energy. Furthermore, possible strategies of inhibiting instability for nanosheets on concave substrates, i.e., reducing its size below the critical length or introducing splicing structures, are proposed and validated. The present findings should be of significant importance for improving instability mechanics of two-dimensional materials and providing guidance for the design and fabrication of various nanodevices.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105390"},"PeriodicalIF":3.4,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144067980","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}