Journal of The Mechanics and Physics of Solids最新文献_第10页

Investigating the formation of a geometrically necessary boundary using discrete dislocation dynamics 利用离散位错动力学研究几何必要边界的形成

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-19 DOI: 10.1016/j.jmps.2025.106069

Felix Frankus , Yash Pachaury , Anter El-Azab , Benoit Devincre , Henning Friis Poulsen , Grethe Winther

引用次数: 0

Measurement of temperature-dependent viscoelastic compressibility of highly-filled thermosets using inert gas pressure 用惰性气体压力测量高填充热固性材料的温度依赖性粘弹性压缩性

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-18 DOI: 10.1016/j.jmps.2025.106087

Sukrut Prashant Phansalkar, Bongtae Han

{"title":"Measurement of temperature-dependent viscoelastic compressibility of highly-filled thermosets using inert gas pressure","authors":"Sukrut Prashant Phansalkar, Bongtae Han","doi":"10.1016/j.jmps.2025.106087","DOIUrl":"10.1016/j.jmps.2025.106087","url":null,"abstract":"<div><div>Highly filled thermosets are widely used to encapsulate chips in the semiconductor packaging industry. A complete set of viscoelastic properties are required for package designs with optimum mechanical reliability. A novel test method, based on inert gas pressure, is proposed and implemented to measure the temperature-dependent viscoelastic hydrostatic creep compliance (or compressibility) of filled thermosets. The method utilizes linearly increasing pressure to mitigate a heat generation problem caused by instantaneous gas pressure application. The hereditary integral for the linear pressure application is derived, and the corresponding normal equations are developed to obtain the generalized Kelvin model constants analytically. The proposed method is implemented using an epoxy-based molding compound. Complete implementation schemes are described, and the compressibility master curve is presented. The validity of the proposed method is verified by supplemental long-term hydrostatic creep tests. The accuracy and repeatability of the proposed method are also discussed.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"199 ","pages":"Article 106087"},"PeriodicalIF":5.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479411","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}

引用次数: 0

Inflation of a polydomain nematic elastomeric membrane 多域向列弹性膜的膨胀

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-17 DOI: 10.1016/j.jmps.2025.106075

Lingrui Zhu, Mengqi He, Baihong Chen, Jin Qian, Rui Xiao

{"title":"Inflation of a polydomain nematic elastomeric membrane","authors":"Lingrui Zhu, Mengqi He, Baihong Chen, Jin Qian, Rui Xiao","doi":"10.1016/j.jmps.2025.106075","DOIUrl":"10.1016/j.jmps.2025.106075","url":null,"abstract":"<div><div>The directors are randomly distributed in polydomain liquid crystal elastomers (LCEs), which can be rearranged upon external loading. This can further lead to a polydomain-monodomain transition, accompanied by a change from an opaque state to a fully transparent state. Currently, the mechanical response and the related phase transition in polydomain LCEs are typically characterized in uniaxial loading conditions. In this work, we employ inflation tests to investigate the complex behaviors of polydomain LCEs under biaxial stress states. Three types of polydomain LCEs were synthesized. The uniaxial tension tests show that the stress–strain curves for all LCEs exhibit a soft stress plateau, followed by a pronounced stress increase with deformation. However, the hardening modulus and the failure stretch ratio differ considerably, leading to distinct responses during inflation processes. For the softest LCEs, a clear snap-through type behavior is observed, while the membrane of the stiffest LCEs fails before reaching the peak pressure value. For the moderately stiff LCEs, the pressure first increases, then reaches a plateau region, and shows a significant increase again. It is further observed that the polydomain-monodomain transition initiates in the bottom part of the membrane balloon and transits to the whole region. For the theoretical aspects, the constitutive relationship of polydomain LCEs is developed through introducing the state variables into the free energy. A numerical model is further constructed to simulate the boundary value problem of inflation tests. The model together with parameters calibrated from the uniaxial tension tests is able to fully capture the response in inflation tests. We also show that the classic hyperelastic models fail to capture the inflation behaviors of polydomain LCE membranes.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"198 ","pages":"Article 106075"},"PeriodicalIF":5.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143438042","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}

引用次数: 0

Phase-augmented digital image correlation for high-accuracy deformation measurement: Theory, validation, and application to constitutive law learning 用于高精度变形测量的相位增强数字图像相关：理论、验证和本构法学习的应用

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-14 DOI: 10.1016/j.jmps.2025.106051

Rahul Danda , Xinxin Wu , Sheng Mao , Yin Zhang , Ting Zhu , Shuman Xia

{"title":"Phase-augmented digital image correlation for high-accuracy deformation measurement: Theory, validation, and application to constitutive law learning","authors":"Rahul Danda , Xinxin Wu , Sheng Mao , Yin Zhang , Ting Zhu , Shuman Xia","doi":"10.1016/j.jmps.2025.106051","DOIUrl":"10.1016/j.jmps.2025.106051","url":null,"abstract":"<div><div>Digital image correlation (DIC) is a prominent technique for full-field, non-contact deformation characterization. Despite its sub-pixel sensitivity for displacement measurement, conventional DIC often suffers from inadequate signal-to-noise ratios (SNRs) when measuring small deformations in stiff and/or brittle materials. This work presents phase-augmented DIC (PA-DIC), a novel method that integrates coherent illumination with image correlation to achieve measurement accuracy that surpasses that of conventional DIC. Unlike conventional DIC, which relies on non-coherent illumination to maintain gray-level conservation during deformation, PA-DIC leverages speckle phase information to measure displacement with improved sensitivity. We applied PA-DIC to characterize rigid-body rotation and non-uniform tensile deformation, validating its high accuracy and reliability. Furthermore, we demonstrated its application for machine learning of an orthotropic elastic constitutive relationship. This was achieved using a hybrid finite element method and neural network (FEM-NN) optimization framework supplied with high-accuracy non-uniform strain data from PA-DIC. With its exceptional measurement accuracy, PA-DIC opens new possibilities for advanced full-field measurement and data-driven material characterization in the small deformation regime.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"198 ","pages":"Article 106051"},"PeriodicalIF":5.0,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418514","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}

引用次数: 0

An extended neo-classical model for nematic elastomers with transversely isotropic semisoft elasticity 具有横向各向同性半软弹性的向列弹性体的扩展新古典模型

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-13 DOI: 10.1016/j.jmps.2025.106077

Donghao Li, Ziang Peng, Yuzhen Chen, Yongzhong Huo

{"title":"An extended neo-classical model for nematic elastomers with transversely isotropic semisoft elasticity","authors":"Donghao Li, Ziang Peng, Yuzhen Chen, Yongzhong Huo","doi":"10.1016/j.jmps.2025.106077","DOIUrl":"10.1016/j.jmps.2025.106077","url":null,"abstract":"<div><div>Nematic elastomers exhibit transversely isotropic semisoft elasticity due to the coupling of the liquid crystal mesogen and polymer network. Existing constitutive models are unable to simultaneously capture both the elastic anisotropy at small deformations and the semisoft stress plateau under large orthogonal loadings. Based on the decompositions of the strain energy and the deformation gradient, we propose an extended neo-classical model for nematic elastomers, which consists of a transversely isotropic soft elastic energy plus a semisoft penalty for the free rotation of the liquid crystal director. The proposed model contains four temperature-dependent material parameters that can be determined through experiments. The determination of the material parameters by thermal-mechanical experiments is illustrated. Also, the temperature dependences of the material parameters are summarized into empirical formulae based on experimental and theoretical studies. Analytical and numerical examples are given to demonstrate that the proposed model can capture both the transversely isotropic elasticity at the small deformations and the stress-induced director rotations with large shear deformations at larger deformations.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"199 ","pages":"Article 106077"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479412","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}

引用次数: 0

Unusual stretching–twisting of liquid crystal elastomer bilayers 液晶弹性体双层不寻常的拉伸扭曲

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-12 DOI: 10.1016/j.jmps.2025.106066

Zhijun Dai , Ya Wen , Zhiang Chen, Yijian Chen, Yifan Yang, Mengdi Gao, Yuzhen Chen, Fan Xu

{"title":"Unusual stretching–twisting of liquid crystal elastomer bilayers","authors":"Zhijun Dai , Ya Wen , Zhiang Chen, Yijian Chen, Yifan Yang, Mengdi Gao, Yuzhen Chen, Fan Xu","doi":"10.1016/j.jmps.2025.106066","DOIUrl":"10.1016/j.jmps.2025.106066","url":null,"abstract":"<div><div>Liquid crystal elastomers (LCEs), as a unique class of smart soft materials combining the properties of liquid crystals and hyperelasticity, are capable of rapid, anisotropic, and reversible deformations in response to mechanical, thermal or optical stimuli. Here, we report a hitherto unknown stretching-induced twisting behavior of LCE bilayer strips. Under uniaxial stretching, we reveal that due to the spontaneous mismatch strain arising from interlayer anisotropy, the bilayer strips exhibit notable twisting deformations. We develop an LCE bilayer strip model based on semi-soft elasticity to quantitatively understand and predict such intriguing tension-twisting response. Based on our experiments and theoretical analyses, we systematically explore how the liquid crystal director orientation, geometric dimensions and material parameters of the strips would affect the twisting behavior. We find that when the alignment of directors of bilayer are symmetric about the stretching direction, a larger deviation angle of the initial directors results in a more significant twisting deformation. Additionally, a longer, narrower and thicker strip has a more pronounced twisting effect. Furthermore, the material anisotropy encourages the twisting, while the feature of semi-soft elasticity discourages it. The findings not only reveal the tension-twisting coupling behavior of LCE bilayer strips, but also offer new insights into the design of LCE actuators, intelligent structures and soft robots.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"198 ","pages":"Article 106066"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418497","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}

引用次数: 0

Analysis of axisymmetric necking of a circular dielectric membrane based on a one-dimensional model 基于一维模型的圆形介质膜轴对称缩颈分析

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-10 DOI: 10.1016/j.jmps.2025.106071

Xiang Yu , Yibin Fu

{"title":"Analysis of axisymmetric necking of a circular dielectric membrane based on a one-dimensional model","authors":"Xiang Yu , Yibin Fu","doi":"10.1016/j.jmps.2025.106071","DOIUrl":"10.1016/j.jmps.2025.106071","url":null,"abstract":"<div><div>To facilitate the understanding of the mechanisms underlying the electric breakdown of dielectric elastomers, we derive a one-dimensional (1d) model for axisymmetric necking in a dielectric membrane subjected to equibiaxial stretching and an electric field, starting from the three-dimensional (3d) nonlinear electroelasticity theory. Our reduction is built on the variational asymptotic method, so that the resulting 1d model is asymptotically self-consistent. The 1d model offers an easier and more efficient way to analyze axisymmetric necking in a dielectric membrane in the linear, weakly nonlinear and fully nonlinear regimes. It delivers results identical to the 3d theory in the linear and weakly nonlinear regimes, and near-identical results in the fully nonlinear regime due to its asymptotic self-consistency. We demonstrate the straightforward implementation of this 1d model by solving it using the Rayleigh–Ritz method and validate it by comparison with finite-element simulations. The 1d model enables a precise calculation of the minimum thickness that a dielectric membrane can reach when necking instability occurs and quantitative assessment of the effects of imperfections so that the integrity of a dielectric elastomer actuator can be evaluated with respect to electric breakdown. The developed methodology is not problem-specific and can also be applied to analyze similar phenomena in other soft materials subjected to any fields (e.g., the axisymmetric necking of stretched plastic membranes).</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"198 ","pages":"Article 106071"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143430203","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}

引用次数: 0

Mechanics of liquid crystal inclusions in soft matrices 软基质中液晶夹杂物的力学研究

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-10 DOI: 10.1016/j.jmps.2025.106070

Yifei Bai, Laurence Brassart

{"title":"Mechanics of liquid crystal inclusions in soft matrices","authors":"Yifei Bai, Laurence Brassart","doi":"10.1016/j.jmps.2025.106070","DOIUrl":"10.1016/j.jmps.2025.106070","url":null,"abstract":"<div><div>The mechanical behaviour of composites of liquid crystal inclusions embedded in soft matrices involves a complex interplay between the elasticity of the matrix, the surface elasticity of the interfaces, and the reorientation of the liquid crystal molecules. Directors of the (nematic) liquid crystal tend to be aligned in the bulk, but may ”anchor” along the interface. In addition, the interface deforms according to the bulk deformation, while trying to minimise the surface area. In this paper, we present a continuum theory for an incompressible hyperelastic matrix containing nematic liquid crystal inclusions. The elastic energy of the inclusions, attributed to the distortion of the director field, is described using Landau–de Gennes theory. The matrix is described as an incompressible neo-Hookean solid. Anchoring effects at the inclusion–matrix interface are described through anisotropic surface tension. The model is implemented numerically using the FEniCSx finite element code. Through parametric study, we investigate the impact of energy competitions on the macroscopic and inclusion responses. Similar to the case of liquid inclusions, composites containing liquid crystal inclusions can be stiffer or softer than the matrix, depending on the value of the elasto-capillary number. The softening or stiffening effect is further affected by the distortional energy of the inclusion and the anchoring strength of the interface. Conversely, applied mechanical loads can reorient the director field. In particular, we show that stress-induced reorientation is significant when the dimensionless volume of the inclusion is large, involving alignment of the directors under tension, and disorientation under compression. The proposed theory and new physical insights could be useful for the design of smart stimuli-responsive materials.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"197 ","pages":"Article 106070"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387598","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}

引用次数: 0

Grid hollow octet truss lattices that are stable at low relative density 在低相对密度下稳定的网格空心八棱桁架

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-08 DOI: 10.1016/j.jmps.2025.106068

Peijie Zhang , Xueyan Chen , Penghui Yu , Kun Zhao , Haoxiang Ma , Shiqiu Liu , Huifeng Tan , Vincent Laude , Muamer Kadic

{"title":"Grid hollow octet truss lattices that are stable at low relative density","authors":"Peijie Zhang , Xueyan Chen , Penghui Yu , Kun Zhao , Haoxiang Ma , Shiqiu Liu , Huifeng Tan , Vincent Laude , Muamer Kadic","doi":"10.1016/j.jmps.2025.106068","DOIUrl":"10.1016/j.jmps.2025.106068","url":null,"abstract":"<div><div>Stretching-dominated lattice materials are renowned for their lightweight nature and exceptional mechanical properties. These materials, however, have historically struggled with scalability towards low relative densities at which they often exhibit unstable oscillation behavior. Here, we propose a viable solution to this issue by integrating hollow truss elements and a grid distribution into the conventional octet truss lattice. The proposed grid hollow octet truss lattices demonstrate significant improvement over the conventional octet truss lattice, with stiffness and specific energy absorption capacities respectively 25.8% and 98% larger. To quantitatively assess the stability of low relative density metamaterials, three metrics are proposed and validated. The effect on the mechanical properties of the octet lattice of the ratio of inner to outer radius and of the grid number are comprehensively investigated numerically. Numerical simulations indicate that larger geometrical parameters and grid numbers significantly enhance the stability of the octet lattice. Consequently, the proposed lattices exhibit comparable energy absorption capacity as smooth shell lattices at equivalent relative density but demonstrate a more stable nonlinear response, maintaining nearly constant stress levels at a relative density of 0.1. Experimental validation supports these findings, highlighting potential for applications to load bearing and energy absorption.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"197 ","pages":"Article 106068"},"PeriodicalIF":5.0,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143377762","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}

引用次数: 0

A unified anisotropic phase field model for progressive failure of fiber-reinforced composite materials 纤维增强复合材料渐进破坏的统一各向异性相场模型

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-02-07 DOI: 10.1016/j.jmps.2025.106063

Yuanfeng Yu , Chi Hou , Meiying Zhao

{"title":"A unified anisotropic phase field model for progressive failure of fiber-reinforced composite materials","authors":"Yuanfeng Yu , Chi Hou , Meiying Zhao","doi":"10.1016/j.jmps.2025.106063","DOIUrl":"10.1016/j.jmps.2025.106063","url":null,"abstract":"<div><div>Fiber-reinforced composite materials have gained considerable traction in various applications due to their exceptional properties, but the multicomponent nature makes their failure modes more complex, so the research of failure mechanism for composites is very important for the safety of the structure in use. In this work, a new unified anisotropic phase field model is proposed. Firstly, a new crack surface density function is developed, drawing on the characteristics of both double and single phase field models, as well as the fracture behavior of composites. This new function retains the advantages of the previous models. Meanwhile, to more accurately portray failure behavior in matrix-dominated fractures, a new mixed-mode damage evolution driving force is presented. In addition, the analytical solution of the model is derived, and the relationships between the model parameters and stress and strain, together with crack bandwidth, are established. Furthermore, 2D and 3D Hashin failure criteria are derived from the phase field model, and the damage initiation criterion and evolution law of the model are constructed. Finally, the new model is validated by some examples, and the influences of the model parameters on the load-displacement response and the crack pattern are analyzed. The simulation results align well with the experimental findings, theoretical analyses, and reference numerical results, demonstrating the validity and accuracy of the presented model.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"197 ","pages":"Article 106063"},"PeriodicalIF":5.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378792","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}

引用次数: 0