Journal of The Mechanics and Physics of Solids最新文献

{"title":"Imperfection-insensitive flexible random network materials with horseshoe microstructures","authors":"Yue Xiao ,&nbsp;Xiaonan Hu ,&nbsp;Jun Wu ,&nbsp;Zhangming Shen ,&nbsp;Shuheng Wang ,&nbsp;Shiwei Xu ,&nbsp;Jianzhong Zhao ,&nbsp;Jiahui Chang ,&nbsp;Yihui Zhang","doi":"10.1016/j.jmps.2024.105968","DOIUrl":"10.1016/j.jmps.2024.105968","url":null,"abstract":"<div><div>Flexible network materials with periodic constructions of bioinspired wavy microstructures are of focusing interest in recent years, because they combine outstanding mechanical performances of low elastic modulus, high stretchability, biomimetic stress-strain responses, and strain-limiting behavior. In practical applications (e.g., bio-integrated devices and tissue engineering), small holes are often strategically designed in flexible network materials to accommodate functional chips and other individual electronic components. The design of imperfection insensitive flexible network materials is therefore of pivotal importance. While random structural constructions are believed to play crucial roles in the excellent mechanical properties of many biological materials, the effect of randomness on mechanical performances of flexible network materials has not yet been explored. In this work, a class of two-dimensional (2D) flexible random network materials consisting of horseshoe microstructures is introduced. Their node distance distributions, which can be characterized by a parameter related to randomness, follow well the Weibull probability density function. Combined numerical and experimental studies were performed to elucidate the effect of randomness on nonlinear mechanical responses of flexible network materials. Simple analytical equations are obtained for their key mechanical properties (e.g., strength, stretchability, and initial modulus). Flexible random network materials (with randomness ≥ 0.4) were found to exhibit approximately isotropic J-shaped stress-strain responses, even in the high-strain regime. Finally, we study the reduction of stretchability and strength in random network materials induced by different types of imperfections (e.g., a missing filament, a missing node, or many missing filaments). In comparison to periodic network materials, random network materials (e.g., with randomness ≥ 0.6) show much smaller reductions of stretchability/strength when the imperfection appears, and are therefore more imperfection-insensitive. Such an imperfection-insensitive behavior can be mainly attributed to a relieved stress concentration around the imperfection of random network materials.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105968"},"PeriodicalIF":5.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical properties of modular assembled composite lattice architecture","authors":"Cheng Gong ,&nbsp;Robert O. Ritchie ,&nbsp;Xingyu Wei ,&nbsp;Qingxu Liu ,&nbsp;Jian Xiong","doi":"10.1016/j.jmps.2024.105967","DOIUrl":"10.1016/j.jmps.2024.105967","url":null,"abstract":"<div><div>The layer-by-layer additive manufacturing approach results in the 3D printed composite lattice structure fails to exploit fiber reinforcement, thereby resulting in inferior mechanical qualities. To address this challenge, this study proposes a novel approach leveraging composite fused filament fabrication (FFF) printing to design modular assembled composite lattice structures. Initially, three high-performance lattice structures were transformed into discrete 2D components and assembled into 3D lattice structures. Subsequently, the mechanical properties of these structures were comprehensively assessed using theoretical, experimental, and finite element analysis methods. Finally, the comparison between the assembled structures and integrated printed lattice structures in terms of surface quality, mechanical properties, and manufacturability revealed significant advantages. The theoretical and finite element analyses accurately predicted the mechanical properties of the lattice structures. The lattice structures that were assembled in a modular way displayed an impressive 74% improvement in surface finish. Additionally, they showed peak strength increases of 140%, 27%, and 26%, respectively, for the mentioned types of topology. The energy absorption also increased significantly by 510.83%, 44.18%, and 30.24%. Furthermore, these assembled structures required less printing support materials, enhancing their manufacturability and cost-effectiveness. This new method of designing modular space structures goes beyond the limitations imposed by equipment by using high-performance topology. It allows for the construction of large-scale, lightweight space structures that offer excellent performance. This study explores innovative opportunities in the field of space manufacturing, offering potential implications for the development of lunar habitats, space telescopes, and space power stations.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105967"},"PeriodicalIF":5.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The positioning of stress fibers in contractile cells minimizes internal mechanical stress","authors":"Lukas Riedel ,&nbsp;Valentin Wössner ,&nbsp;Dominic Kempf ,&nbsp;Falko Ziebert ,&nbsp;Peter Bastian ,&nbsp;Ulrich S. Schwarz","doi":"10.1016/j.jmps.2024.105950","DOIUrl":"10.1016/j.jmps.2024.105950","url":null,"abstract":"<div><div>The mechanics of animal cells is strongly determined by stress fibers, which are contractile filament bundles that form dynamically in response to extracellular cues. Stress fibers allow the cell to adapt its mechanics to environmental conditions and to protect it from structural damage. While the physical description of single stress fibers is well-developed, much less is known about their spatial distribution on the level of whole cells. Here, we combine a finite element method for one-dimensional fibers embedded in an elastic bulk medium with dynamical rules for stress fiber formation based on genetic algorithms. We postulate that their main goal is to achieve minimal mechanical stress in the bulk material with as few fibers as possible. The fiber positions and configurations resulting from this optimization task alone are in good agreement with those found in experiments where cells in 3D-scaffolds were mechanically strained at one attachment point. For optimized configurations, we find that stress fibers typically run through the cell in a diagonal fashion, similar to reinforcement strategies used for composite material.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105950"},"PeriodicalIF":5.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Latent-Energy-Based NNs: An interpretable Neural Network architecture for model-order reduction of nonlinear statics in solid mechanics","authors":"Louen Pottier ,&nbsp;Anders Thorin ,&nbsp;Francisco Chinesta","doi":"10.1016/j.jmps.2024.105953","DOIUrl":"10.1016/j.jmps.2024.105953","url":null,"abstract":"<div><div>Nonlinear mechanical systems can exhibit non-uniqueness of the displacement field in response to a force field, which is related to the non-convexity of strain energy. This work proposes a Neural Network-based surrogate model capable of capturing this phenomenon while introducing an energy in a latent space of small dimension, that preserves the topology of the strain energy; this feature is a novelty with respect to the state of the art. It is exemplified on two mechanical systems of simple geometry, but challenging strong nonlinearities. The proposed architecture offers an additional advantage over existing ones: it can be used to infer both displacements from forces, or forces from displacements, without being trained in both ways.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"194 ","pages":"Article 105953"},"PeriodicalIF":5.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implicit implementation of a coupled transformation – plasticity crystal mechanics model for shape memory alloys that includes transformation rotations","authors":"Rupesh K. Mahendran ,&nbsp;Surya R. Kalidindi ,&nbsp;Aaron P. Stebner","doi":"10.1016/j.jmps.2024.105964","DOIUrl":"10.1016/j.jmps.2024.105964","url":null,"abstract":"<div><div>A rate-dependent crystal-plasticity (CP) framework that captures the coupled phase transformation - plastic deformation behavior of shape memory alloys (SMAs) is presented. Here, different from previous models, the flow rule for martensitic phase transformation incorporates the entire deformation gradient for transformation, including the rotation. Predictions of transformation strain and variant selection of Nickel-Titanium (NiTi) using this model are directly compared with previous formulations that did not include the rotation. The results show that the rotation is essential to accurately calculate the single crystal and polycrystal micromechanics of variant selection and transformation strains of SMAs. The constitutive law formulation also includes current formulations for both slip and deformation twinning plasticity mechanisms, and the differences in transformation mechanisms are further shown to impact plasticity calculations through transformation-plasticity interactions. In addition to the advancement of the constitutive law, a computationally efficient implicit time integration scheme is given for numerical implementation and demonstrated using a user material subroutine (UMAT) in the commercial finite element code ABAQUS Standard. The proposed framework and the associated numerical protocols achieve stable solutions using strain increments on the order of <span><math><mrow><mn>0.05</mn></mrow></math></span> mm/mm in simulating inelastic deformations and strain increments <span><math><mrow><mn>0.01</mn></mrow></math></span> mm/mm in the elastic-inelastic transitions. Furthermore, the use of an analytic Jacobian results in stable convergence in fewer than 10 global Newton iterations while calculating solutions for elastic-inelastic transitions, making the computational benefits evident.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105964"},"PeriodicalIF":5.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strain localization in rate sensitive porous ductile materials","authors":"Alok Tripathy,&nbsp;Shyam M. Keralavarma","doi":"10.1016/j.jmps.2024.105957","DOIUrl":"10.1016/j.jmps.2024.105957","url":null,"abstract":"<div><div>Ductile failure by the onset of strain localization in rate sensitive porous materials is investigated using a linear perturbation stability analysis. A micromechanics-based constitutive model accounting for inhomogeneous yielding at the micro-scale, due to plastic strain concentration in the inter-void ligaments, is used. Strain and strain rate hardening of the material is accounted for using a phenomenological viscoplastic extension of the model. Unlike in earlier studies employing a rate-dependent model, an analytical closed form expression for the critical value of the hardening modulus at the onset of localization is derived. The predicted shape of the failure locus under proportional loading is shown to be consistent with known results in the literature for the loading path dependence of ductile failure. The model predicted failure loci are validated by comparison with mesoscopic unit cell model simulations of void growth in a viscoplastic power law hardening material. It is shown that the failure strains predicted by the model as a function of the hardening parameters are in good agreement with the strains to the onset of elastic unloading in the cell model simulations, signifying the onset of void coalescence at the micro-scale.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105957"},"PeriodicalIF":5.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graph neural networks for strut-based architected solids","authors":"I. Grega ,&nbsp;I. Batatia ,&nbsp;P.P. Indurkar ,&nbsp;G. Csányi ,&nbsp;S. Karlapati ,&nbsp;V.S. Deshpande","doi":"10.1016/j.jmps.2024.105966","DOIUrl":"10.1016/j.jmps.2024.105966","url":null,"abstract":"<div><div>Machine learning methods for strut-based architected solids are attractive for reducing computational costs in optimisation calculations. However, the space of all realizable strut-based periodic architected solids is vast: not only can the number of nodes, their positions and the radii of the struts be changed but the topological variables such as the connectivity of the nodes brings significant complexity. In this work, we first examine the structure-property relationships of a large dataset of strut-based architected solids (lattices). We enrich the dataset by perturbing nodal positions and observe four classes of mechanical behaviour. A graph neural network (GNN) method is then proposed that directly describes the topology of the strut-based architected solid as a graph. The differentiating feature of our work is that key physical principles are embedded into the GNN architecture. In particular, the GNN model predicts fourth-order tensor with the required major and minor symmetries. The predictions are equivariant to rigid body and self-similar transformations, invariant to the choice of unit cell and constrained to provide a positive semi-definite stiffness tensor. We further demonstrate that augmenting the training dataset with nodal perturbations enables the model to better generalize to unseen lattice topologies.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105966"},"PeriodicalIF":5.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stochastic generalized standard materials and risk-averse effective behavior","authors":"Jeremy Bleyer","doi":"10.1016/j.jmps.2024.105952","DOIUrl":"10.1016/j.jmps.2024.105952","url":null,"abstract":"<div><div>In this work, we develop a theoretical formulation for describing dissipative material behaviors in a stochastic setting, using the framework of Generalized Standard Materials (GSM). Our goal is to capture the variability inherent in the material model while ensuring thermodynamic consistency, by employing the mathematical framework of stochastic programming. We first show how average behaviors can be computed using the expected value of the free energy and dissipation pseudo-potentials. We then introduce the concept of a risk-averse effective measure, which provides both an optimistic and a pessimistic estimate of the uncertain material behavior. To this end, we utilize the Conditional Value-at-Risk, a widely used risk measure in mathematical finance. We also demonstrate how these concepts can be extended to variational problems at the structure scale, allowing us to compute the effective response of a structure composed of a stochastic material.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105952"},"PeriodicalIF":5.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanics of electroadhesion of polyelectrolyte hydrogel heterojunctions enabled by ionic double layers","authors":"Zheyu Dong,&nbsp;Zhi Sheng,&nbsp;Zihang Shen,&nbsp;Shaoxing Qu,&nbsp;Zheng Jia","doi":"10.1016/j.jmps.2024.105960","DOIUrl":"10.1016/j.jmps.2024.105960","url":null,"abstract":"<div><div>In recent years, soft materials with reversible adhesion have come to the fore as a promising avenue of research. Compared to other reversible adhesion methods, electroadhesion enabled by the formation of ionic double layer (IDL) has been widely used due to its simplicity, low energy consumption, fast response, and reversibility. Despite the extensive experimental studies and qualitative mechanistic explanations, there remains a dearth of theoretical studies on this topic, particularly regarding the development of theoretical mechanics models. Our study aims to address this gap by establishing a mechanics model of IDL-enabled electroadhesion between soft materials. We specifically focus on modeling the low-voltage electroadhesion of heterojunctions between two polyelectrolyte hydrogels. The model decomposes the electroadhesion formation into two successive physical processes. First, under appropriate bias conditions, the applied voltage drives the mobile ions in each polyelectrolyte hydrogel to migrate toward the electrode, resulting in the formation of an IDL at the heterojunction interface and the generation of a potent built-in electric field inside the IDL. Second, driven by the strong built-in electric field of IDL, the dangling charged chains of the two polyelectrolyte hydrogels begin to cross the heterojunction interface and penetrate into the opposite hydrogel matrix to form ionic bonds with the oppositely-charged chains, resulting in a bridging network that sutures the interface. As a result, the electrostatic interactions inside the IDL as well as the bridging network across the interface leads to the electroadhesion of polyelectrolyte hydrogel heterojunctions. The modeling results show that the IDL thickness, the IDL electric field density, and the electroadhesion strength increase with the applied voltage. We also experimentally conduct the electroadhesion tests, and the measurements of electroadhesion strength quantitatively match the modeling results well. For the first time, we reveal the underlying mechanism of IDL-driven electroadhesion by establishing a theoretical mechanics model. We anticipate that our mechanics model can shed light on the design, optimization, and control of the electroadhesion of soft-material heterojunctions.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105960"},"PeriodicalIF":5.0,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the molecular mechanisms of membrane rupture: Insights from all-atom simulations and theoretical modeling","authors":"Panpan Zhu ,&nbsp;Ji Lin ,&nbsp;Yimou Fu ,&nbsp;Chun Shen ,&nbsp;Haofei Zhou ,&nbsp;Shaoxing Qu ,&nbsp;Huajian Gao","doi":"10.1016/j.jmps.2024.105958","DOIUrl":"10.1016/j.jmps.2024.105958","url":null,"abstract":"<div><div>Cell membrane rupture occurs universally and is long thought to be the terminal event of cell death; however, there is an inadequate understanding of the microscopic mechanisms of membrane rupture at the molecular level. In this study, we investigated the rupture mechanism of two model membranes, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and cholesterol bilayer membranes, under surface tension by all-atom molecular simulations and theoretical modeling. Under surface tension, the tail chains of POPC molecules become disordered, leading to ductile membrane deformation, while cholesterol membranes display limited deformation before rupture. We analyzed the orientation of tail chains and the internal stresses within the membranes, revealing that the mutual attraction among different tail chains and the resulting stress peak in the tail region of the membrane play substantial roles in the membrane rupture process. Based on these physical insights, we proposed a theoretical model that incorporates an internal variable of tail chain orientation to capture the variations in strain and orientation of different membrane components under varying surface tensions. The critical rupture threshold predicted by our theoretical model aligns well with the simulation results, demonstrating a brittle to ductile transition for membranes with different cholesterol contents. Our study unravels the impact of tail chain orientation and internal stress on membrane mechanics, which deepens the understanding of the microscale mechanisms underlying membrane rupture.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105958"},"PeriodicalIF":5.0,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}