Journal of The Mechanics and Physics of Solids最新文献

{"title":"Foldable piecewise linear origami that approximates curved tile origami","authors":"Huan Liu,&nbsp;Richard D. James","doi":"10.1016/j.jmps.2024.105962","DOIUrl":"10.1016/j.jmps.2024.105962","url":null,"abstract":"<div><div>Curved origami featuring curved tiles can store elastic energy and bias the structure toward a desired shape when subjected to appropriate constraints. Without constraints, however, a curved origami structure generally has infinitely many degrees of freedom. For engineering applications in which a particular folding motion is desired, a great many constraints have to be introduced. One natural strategy to reduce degrees of freedom is to discretize curved origami into piecewise linear origami while closely approximating the desired curved folding motion. Then, as we show, the degrees of freedom are vastly reduced (typically to one DoF in cases where the folding angle at the crease is not trivial, and excluding overall rigid body motions). In this paper we present a Lagrangian approach for constructing curved origami structures which is complementary to our approach in Liu and James (2024). Then, we generalize this approach to allow quite general curved creases. We outline a way to discretize curved crease patterns and present two optimization methods to refine these patterns. Our approach ensures that the deformed piecewise linear origami closely matches the folding angles and crease configurations of the curved origami. Piecewise linear origami structures that approximate curved origami offer promising potential for architectural and robotic design applications. They also give an efficient way to design desired smooth structures by optimizing finite-dimensional piecewise linear structures.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105962"},"PeriodicalIF":5.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747878","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":"Explicit topography design for complex shell structures based on embedded spline components","authors":"Wendong Huo ,&nbsp;Chang Liu ,&nbsp;Yilin Guo ,&nbsp;Zongliang Du ,&nbsp;Weisheng Zhang ,&nbsp;Xu Guo","doi":"10.1016/j.jmps.2024.105974","DOIUrl":"10.1016/j.jmps.2024.105974","url":null,"abstract":"<div><div>The slender property of shell structures causes the magnitude difference between in-plane and out-of-plane stiffness. Inspired by such a geometry-induced anisotropy phenomenon, this paper proposes a novel design approach to improve the stiffness of complex shell structures. The optimization algorithm is constructed based on two technical pillars, i.e., the explicit moving morphable components (MMC) framework and the computational conformal mapping (CCM) technique. Owing to the MMC framework, the proposed approach can describe complex topography fields with local details via relatively few design variables, theoretically decreasing the computation burden. Towards shell structures in practice, of which the geometry models are usually flexible and complex, we leverage the CCM technique to parameterize the middle surfaces to obtain a unified and robust algorithm architecture. Representative examples with complex geometry models are provided to validate the proposed design method's effectiveness, efficiency, and universality.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 105974"},"PeriodicalIF":5.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788885","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":"Modeling abscission of cacti branches","authors":"Ludwig Striet ,&nbsp;Max D. Mylo ,&nbsp;Olga Speck ,&nbsp;Patrick W. Dondl","doi":"10.1016/j.jmps.2024.105965","DOIUrl":"10.1016/j.jmps.2024.105965","url":null,"abstract":"<div><div>During evolution, various functional principles have evolved that allow plants to create predetermined breaking points for the spatially defined abscission of organs. In the plant family of cacti, some species, such as <em>Cylindropuntia bigelovii</em>, have fragile branch–branch junctions that serve vegetative reproduction, while in other species, such as <em>Opuntia ficus-indica</em>, they are very stable. The fracture behavior of these junctions has been thoroughly characterized anatomically and mechanically, the data being the prerequisite for the performance of cactus-inspired phase field simulations. We have found that models composed of homogeneous materials or material systems with low elastic modulus contrast (analogous to <em>Cylindropuntia bigelovii</em>) exhibit a fracture mode where cracks initiation occurs at the epidermis of the junction notch. In comparison, heterogeneous material systems with high elastic modulus contrast (similar to <em>Opuntia ficus-indica</em>) show fracture nucleation along the inner vascular bundles, with an increase in the maximum fracture energy by a factor of 2.2. In the high contrast heterogeneous models, the V-notch and stiffening of the dermal tissue (“periderm”) have a negligible effect on their fracture behavior. In addition, the fracture morphologies of these models resemble the rough junction fracture sites found experimentally. The knowledge gained about the geometric influences and the importance of the contrasts in the mechanical properties of the individual materials in the overall system can be transferred as functional principles to bioinspired engineering composites in order to program their fracture behavior.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 105965"},"PeriodicalIF":5.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788955","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":"Capillary rise in a packing of glass spheres","authors":"Ratul Das,&nbsp;Vikram S. Deshpande,&nbsp;Norman A. Fleck","doi":"10.1016/j.jmps.2024.105963","DOIUrl":"10.1016/j.jmps.2024.105963","url":null,"abstract":"<div><div>A series of experiments are performed to give insight into the mechanisms of liquid rise in a 3D dense random packing of glass spheres. A sharp knee in the log-log plot of water height <em>h</em> versus time <em>t</em> curve is observed, with an attendant change in <em>h</em>(<em>t</em>) characteristic from <span><math><mrow><mi>h</mi><mo>∝</mo><msup><mi>t</mi><mrow><mn>0.5</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mi>h</mi><mo>∝</mo><msup><mi>t</mi><mrow><mn>0.05</mn></mrow></msup></mrow></math></span>. This behaviour is observed for 5 choices of diameter distribution of spheres, such that the mean diameter is in the range of 0.22 mm to 1.20 mm, and the ratio of standard deviation to mean diameter lies between 0.014 and 0.157. Immediate arrest in water rise occurs when the water reservoir is removed from the bottom of the column, in support of the conclusion that water rise is by capillary action. In the post-knee regime of the <em>h</em>(<em>t</em>) response, water rise occurs in a jerky manner by a series of jumps, involving transverse jumps and more occasional vertical jumps in water ingress; each jump is by an increment of sphere diameter. The incubation time for each vertical jump is sensitive to height of meniscus and dictates the overall rate of water rise. Pendular-rings at the junctions between glass spheres are not observed above the meniscus; this casts doubt upon the notion that the jerky motion of the meniscus is due to the incubation time for a vapour-fed pendular-ring to grow and coalesce with the meniscus. Possible sources of the height-dependent incubation time for each vertical jump are discussed, including a time-dependent increase in surface tension. Additional insight is obtained by observing water rise, and glycerol rise in (i) a monolayer of glass spheres, (ii) in a capillary tube of diameter slightly greater than that of the glass beads and filled with a single column of glass spheres and (iii) an empty capillary tube. Continued liquid rise beyond the knee in the <em>h</em>(<em>t</em>) curve is noted in all cases except for that of an empty capillary tube.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 105963"},"PeriodicalIF":5.0,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142788957","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":"Modeling direct and converse flexoelectricity in soft dielectric rods with application to the follower load","authors":"Pushkar Mishra,&nbsp;Prakhar Gupta","doi":"10.1016/j.jmps.2024.105956","DOIUrl":"10.1016/j.jmps.2024.105956","url":null,"abstract":"<div><div>Dielectric rods have been employed in various electromechanical applications, including energy harvesters and sensors. This paper develops a general framework to model large deformations in dielectric rods, considering both direct and converse flexoelectric effects. Initially, we derive the governing differential equations for a three-dimensional dielectric continuum solid to model large deformations, incorporating converse flexoelectricity. Then, we derive the equilibrium equations for the flexoelectric strain-gradient special Cosserat rod. Subsequently, we establish its constitutive relations and identify the corresponding work conjugates. To solve these governing differential equations numerically, we implement a quaternion-based numerical approach and obtain flexoelectricity-based solutions corresponding to the follower load. Moreover using these constitutive relations, we have also obtained nonlinear analytical solutions for bending under the follower load that show an excellent agreement with our numerical results. Bending under the follower load is also compared with the transverse load to understand the electric field generation. Unlike, under the application of the transverse load, where the electric field increases monotonically, for the follower load, the electric field gradually switches its sign. The role of direct and converse flexoelectric coefficients has also been examined, and several interesting conclusions have been drawn. Finally, we analyze the effect of mechanical and electrical length scale parameters. The electromechanical response from the follower load can be utilized to fabricate flexoelectric sensors for nanoelectromechanical systems.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105956"},"PeriodicalIF":5.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747879","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":"Multi-scale modeling of hydrogel-based concrete formed under the ambient environment and the extremely harsh environment of Mars","authors":"Ning Liu,&nbsp;Tianju Xue,&nbsp;Jishen Qiu","doi":"10.1016/j.jmps.2024.105969","DOIUrl":"10.1016/j.jmps.2024.105969","url":null,"abstract":"<div><div>Hydrogel-based concretes (HBCs) are an emerging class of load-bearing composite materials consisting of inert particles joined together by micro-hydrogel joints. As HBCs can harden via sol-gel process and H₂O phase changes under a freezing temperature and vacuum, they are suitable for future exterritorial constructions. Previous studies have demonstrated that the internal microstructure of the hydrogel joints in HBC varies significantly with curing temperature and air pressure, leading to variations in their mechanical properties. In this study, we present a new multi-scale model that quantitatively predicts the mechanical properties of HBC formed under different curing environments including Martian atmosphere. On the micro-scale, four representative joint microstructures are studied, including tubular, foamy, honeycomb, and tube-cased-foam joints. We experimentally studied and analytically derived the constitutive relationship between the joint force and displacement. Particularly, we determined the process of hydrogel skin peeling from the particle's surface of tubular joints based on force and energy equilibrium. On the macro-scale, we simplified the constitutive joint relationships in a linear parallel bond model (LPM) and employed them to quantify interparticle relationships in a discrete element method (DEM)-based HBC model. The Weibull distribution is used to consider the variation of tensile and shear strengths of the hydrogel joints in the DEM. The modeling results are not only validated with the experimentally acquired compressive stress-strain curves of HBC, but also accurately predict the combined influence of mix design and curing conditions on the mechanical properties.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 105969"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163820","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":"Modeling spider silk supercontraction as a hydration-driven solid–solid phase transition","authors":"Vincenzo Fazio ,&nbsp;Giuseppe Florio ,&nbsp;Nicola Maria Pugno ,&nbsp;Giuseppe Puglisi","doi":"10.1016/j.jmps.2024.105959","DOIUrl":"10.1016/j.jmps.2024.105959","url":null,"abstract":"<div><div>Spider silks have attracted significant interest due to their exceptional mechanical properties, which include a unique combination of high strength, ultimate strain, and toughness. A notable characteristic of spider silk, still debated from both mechanical and functional viewpoints, is supercontraction –a pronounced contraction of up to half its original length when an unconstrained silk thread is exposed to a wet environment. We propose a predictive model for the hygro-thermo-mechanical behavior of spider silks, conceptualizing this phenomenon as a solid–solid phase transition, similar to the glass transition in rubber, but driven by humidity. As wetting increases, the system undergoes a transition, at the network scale, from a hard, dry state –where the material behavior is governed by stiff chains elongated along the fiber axis– to a soft, wet state, regulated by a rubber-like response. We model these states using a two-well free energy function dependent on molecular stretch, with transition energy modulated by humidity. Based on the methods of Statistical Mechanics, we deduce that supercontraction can be interpreted as a solid–solid phase transition. We elucidate the important role of thermal fluctuations. In particular, the decrease of the critical humidity needed for supercontraction as temperature grows results as an effect of entropic stabilization of the softer rubbery phase. Our model quantitatively predicts the observed experimental behavior, capturing the temperature dependence of humidity-induced supercontraction effects and related cooperative properties.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105959"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747877","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":"Homogenization of phase transforming materials: The concept of phase-morphology and variable scale separations","authors":"Vincent von Oertzen,&nbsp;Bjoern Kiefer","doi":"10.1016/j.jmps.2024.105961","DOIUrl":"10.1016/j.jmps.2024.105961","url":null,"abstract":"<div><div>Phase transforming solids are in focus of modern engineering applications due to their promising mechanical properties, which originate from a change of microstructure in stress- and temperature induced loading scenarios. The transition of respective evolution laws, describing these characteristic phase changes, between several spatial (and temporal) scales through appropriate homogenization techniques is the key to understand and simulate large scale behavior of these materials. Whereas in most of the relevant literature the microstructure is only analyzed in the relaxed and thus fully transformed system state, this work aims to derive the effective material behavior <em>during</em> the phase evolution process. More specifically, a homogenization theory is presented for systems in which the conventional notion of scale separation changes over time. This involves the introduction of new concepts of so-called <em>phase-morphology</em> and <em>variable scale separation</em>. The developed homogenization theory is applied to the material ZrO₂ in order to derive its effective driving force at variable scales and macroscopic elastic properties, both as a function of the temporally changing microstructural topology. Moreover, the martensite re-orientation during undercooling simulations is analyzed, thus demonstrating that the concept of phase-morphology can also serve as an indicator for the stationarity of phase distributions during a transformation process. The results agree with those obtained from one- and two-dimensional finite element simulations up to a negligible tolerance, which proves the validity of the outlined homogenization approach.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105961"},"PeriodicalIF":5.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747981","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":"Finite strain continuum phenomenological model describing the shape-memory effects in multi-phase semi-crystalline networks","authors":"Matteo Arricca ,&nbsp;Nicoletta Inverardi ,&nbsp;Stefano Pandini ,&nbsp;Maurizio Toselli ,&nbsp;Massimo Messori ,&nbsp;Giulia Scalet","doi":"10.1016/j.jmps.2024.105955","DOIUrl":"10.1016/j.jmps.2024.105955","url":null,"abstract":"<div><div>Thermally-driven semi-crystalline polymer networks are capable to achieve both the one-way shape-memory effect and two-way shape-memory effect under stress and stress-free conditions, therefore representing an appealing class of polymers for applications requiring autonomous reversible actuation and shape changes. In these materials, the shape-memory effects are achieved by leveraging the synergistic interaction between one or more crystalline phases and the surrounding amorphous ones that are present within the network itself. The present paper introduces a general framework for the finite strain continuum phenomenological modeling of the thermo-mechanical and shape-memory behavior of multi-phase semi-crystalline polymer networks. Model formulation, including the definition of phase and control variables, kinematic assumptions, and constitutive specifications, is introduced and thoroughly discussed. Theoretical derivations are general and easily adaptable to all cross-linked systems which include two or more crystalline domains or a single crystalline phase with a wide melting range and manifest macroscopically the one-way shape-memory effect and the two-way shape-memory effect under stress and stress-free conditions. Model capabilities are validated against experimental data for copolymer networks with two different crystalline phases characterized by well-separated melting and crystallization transitions. Results demonstrate the accuracy of the proposed model in predicting all the phenomena involved and in furnishing a useful support for future material and application design purposes.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105955"},"PeriodicalIF":5.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704810","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":"A static and dynamic theory for photo-flexoelectric liquid crystal elastomers and the coupling of light, deformation and electricity","authors":"Amir Hossein Rahmati ,&nbsp;Kosar Mozaffari ,&nbsp;Liping Liu ,&nbsp;Pradeep Sharma","doi":"10.1016/j.jmps.2024.105949","DOIUrl":"10.1016/j.jmps.2024.105949","url":null,"abstract":"<div><div>Photoactive nematic liquid crystal elastomers permit generation of large mechanical deformation through impingement by suitably polarized light. The light-induced deformation in this class of soft matter allows for devices such as transducers and robots that may be triggered wirelessly. While there is no ostensible direct coupling between light and electricity in nematic liquid crystal elastomers, in this work, we take cognizance of the fact that the phenomenon of flexoelectricity is universal and present in all dielectrics. Flexoelectricity involves generation of electrical fields due to strain gradients or conversely, the production of mechanical deformation through electrical fields. Barring some specific contexts, the flexoelectric effect is in general rather weak in <em>hard</em> materials. However, due to the facile realization of strain gradients (e.g. flexure) in soft materials, we expect flexoelectricity to be highly relevant for liquid crystal elastomers thus, <em>prima facie</em>, furnishing a deformation-mediated mechanism to couple light and electricity. In this work, we develop nonlinear equilibrium and dynamical models for photo-flexoelectric nematic liquid crystal elastomers and analyze the precise conditions underpinning an appreciable coupling between light and electricity. A careful scaling analysis reveals that there is an optimal size-scale at which the flexoelectricity-mediated photo-electric effect is maximized. We find that with conservative estimates of the flexoelectric coefficients of these materials, the electrical power generation is rather modest for typical optical load. However, our proposed coupling is an appropriate modality for optical sensing. Furthermore, design of next-generation liquid crystal elastomers with high flexoelectricity as well as exploitation of size-effects could ameliorate extraction of electrical power from light illumination.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"195 ","pages":"Article 105949"},"PeriodicalIF":5.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719805","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}