Continuum Mechanics and Thermodynamics最新文献

{"title":"Multiscale investigation of debonding behavior in anisotropic graphene–polyethylene metamaterial nanocomposites","authors":"M. Safaei,&nbsp;M. R. Karimi,&nbsp;D. Pourbandari,&nbsp;M. Baghani,&nbsp;D. George,&nbsp;M. Baniassadi","doi":"10.1007/s00161-024-01328-x","DOIUrl":"10.1007/s00161-024-01328-x","url":null,"abstract":"<div><p>The first phase of this study aimed to validate multi-scale approaches based on Representative Volume Elements (RVEs) for graphene–polyethylene nanocomposites.\u0000 stress–strain curves of experimental results were compared with numerical homogenization results. The stress amplification obtained from these simulations was used to predict GNP aspect ratios, demonstrating good agreement with permeability results. After validation of the multiscale approach, this study investigates the adhesion between nanoparticles and matrix in anisotropic GNP-HDPE metamaterial nanocomposites, emphasizing the role of the carboxyl (COOH) functional group in improving adhesion. The RVE model is used to investigate the debonding initiation and progression in these anisotropic nanocomposites under tensile and shear loading. Results indicate a variance in debonding onset and growth depending on orientation relative to the GNP axis. In tensile loading, debonding initiates at higher strains along the GNP axis than perpendicularly. Under shear loading within an anisotropic distribution, debonding behaviour varies significantly between planes perpendicular and parallel to the GNP axis. GNP surfaces with fully debonded surfaces slightly exceed 0.6% perpendicular to the GNP axis but increase to over 10.5% parallel to it.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1767 - 1785"},"PeriodicalIF":1.9,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-scale homogenization framework for design and strain-gradient modeling of additively manufactured parts fabricated by particulate composites","authors":"B. Cagri Sarar,&nbsp;M. Erden Yildizdag,&nbsp;B. Emek Abali","doi":"10.1007/s00161-024-01320-5","DOIUrl":"10.1007/s00161-024-01320-5","url":null,"abstract":"<div><p>Classical homogenization approaches applied to heterogeneous materials are suitable for the cases where a scale-separation is eminent. As the length-scale at the effective continuum reaches the length-scale of the microstructure of the material, classical homogenization approaches fail to be accurate. In such cases, higher-gradient theories may be stimulated for multi-scale material modeling of complex structures in terms of geometry and material. In this study, a multi-scale homogenization framework is presented for additively manufactured (3-D printed) composite parts with specific infill design. The overall framework consists of two major steps, namely micro-to-material and material-to-structure homogenization. In both steps, an asymptotic homogenization procedure is applied to determine constitutive parameters. In the micro-to-material homogenization, the constitutive parameters of the composite material are first determined regarding the material composition. Then, in the material-to-structure homogenization, the constitutive parameters are obtained regarding the infill design of the additively manufactured part. The developed two-step homogenization framework is applied for an off-the-shelf composite material commonly used in 3-D printers. Specifically, in this study, composite parts printed with grid infills are investigated numerically considering different infill ratios.\u0000</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1629 - 1643"},"PeriodicalIF":1.9,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142090067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exact hydrodynamic manifolds for the linear Boltzmann BGK equation I: spectral theory","authors":"Florian Kogelbauer,&nbsp;Ilya Karlin","doi":"10.1007/s00161-024-01323-2","DOIUrl":"10.1007/s00161-024-01323-2","url":null,"abstract":"<div><p>We perform a complete spectral analysis of the linear three-dimensional Boltzmann BGK operator resulting in an explicit transcendental equation for the eigenvalues. Using the theory of finite-rank perturbations, we confirm the existence of a critical wave number <span>(k_{textrm{crit}})</span> which limits the number of hydrodynamic modes in the frequency space. This implies that there are only finitely many isolated eigenvalues above the essential spectrum at each wave number, thus showing the existence of a finite-dimensional, well-separated linear hydrodynamic manifold as a combination of invariant eigenspaces. The obtained results can serve as a benchmark for validating approximate theories of hydrodynamic closures and moment methods and provides the basis for the spectral closure operator.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1685 - 1709"},"PeriodicalIF":1.9,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00161-024-01323-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142002775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Wave solutions in nonlocal integral beams","authors":"Raffaele Barretta,&nbsp;Annalisa Iuorio,&nbsp;Raimondo Luciano,&nbsp;Marzia Sara Vaccaro","doi":"10.1007/s00161-024-01319-y","DOIUrl":"10.1007/s00161-024-01319-y","url":null,"abstract":"<div><p>Wave propagation in slender beams is addressed in the framework of nonlocal continuum mechanics. The elastodynamic problem is formulated exploiting consistent methodologies of pure integral, mixture and nonlocal strain gradient elasticity. Relevant wave solutions are analytically provided, with peculiar attention to reflection and near field phenomena occurring in presence of boundaries. Notably, the solution field is got as superimposition of incident, reflected, primary near field and secondary near field waves. The latter contribution represents a further effect due to the size dependent mechanical behaviour. Limit responses for vanishing nonlocal parameter are analytically evaluated, consistently showing a zero amplitude of the secondary near field wave. Parametric analyses are carried out to show how length scale parameter, amplitude of incident wave and geometric and elastic properties of the beam affect the amplitudes of reflected, primary near field and secondary near field waves. The results obtained exploiting different nonlocal integral elasticity approaches are compared and discussed.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1607 - 1627"},"PeriodicalIF":1.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00161-024-01319-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141994369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Mathematical modelling of stability problems for thin transversally graded cylindrical shells","authors":"B. Tomczyk,&nbsp;M. Gołąbczak,&nbsp;E. Kubacka,&nbsp;V. Bagdasaryan","doi":"10.1007/s00161-024-01322-3","DOIUrl":"10.1007/s00161-024-01322-3","url":null,"abstract":"<div><p>The objects of consideration are thin linearly elastic Kirchhoff–Love-type open circular cylindrical shells having a functionally graded macrostructure and a tolerance-periodic microstructure in circumferential direction. The first aim of this contribution is to formulate and discuss <i>a new mathematical averaged non-asymptotic model for the analysis of selected stability problems for such shells</i>. As a tool of modelling we shall apply <i>the tolerance averaging technique</i>. The second aim is to derive and discuss <i>a new mathematical averaged asymptotic model</i>. This model will be formulated using <i>the consistent asymptotic modelling procedure</i>. The starting equations are the well-known governing equations of linear Kirchhoff–Love second-order theory of thin elastic cylindrical shells. For the functionally graded shells under consideration, the starting equations have highly oscillating, non-continuous and tolerance-periodic coefficients in circumferential direction, whereas equations of the proposed models have continuous and slowly-varying coefficients. Moreover, some of coefficients of the tolerance model equations depend on a microstructure size. It will be shown that in the framework of the tolerance model <i>not only the fundamental cell-independent, but also the new additional cell-dependent critical forces can be derived and analysed.</i></p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1661 - 1684"},"PeriodicalIF":1.9,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00161-024-01322-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141895358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 review of inverse problems for generalized elastic media: formulations, experiments, synthesis","authors":"Roberto Fedele,&nbsp;Luca Placidi,&nbsp;Francesco Fabbrocino","doi":"10.1007/s00161-024-01314-3","DOIUrl":"10.1007/s00161-024-01314-3","url":null,"abstract":"<div><p>Starting from the seminal works of Toupin, Mindlin and Germain, a wide class of generalized elastic models have been proposed via the principle of virtual work, by postulating expressions of the elastic energy enriched by additional kinematic descriptors or by higher gradients of the placement. More recently, such models have been adopted to describe phenomena which are not consistent with the Cauchy-Born continuum, namely the size dependence of apparent elastic moduli observed for micro and nano-objects, wave dispersion, optical modes and band gaps in the dynamics of heterogeneous media. For those structures the mechanical response is affected by surface effects which are predominant with respect to the bulk, and the scale of the external actions interferes with the characteristic size of the heterogeneities. Generalized continua are very often referred to as media with microstructure although a rigorous deduction is lacking between the specific microstructural features and the constitutive equations. While in the forward modelling predictions of the observations are provided, the actual observations at multiple scales can be used inversely to integrate some lack of information about the model. In this review paper, generalized continua are investigated from the standpoint of inverse problems, focusing onto three topics, tightly connected and located at the border between multiscale modelling and the experimental assessment, namely: (i) parameter identification of generalized elastic models, including asymptotic methods and homogenization strategies; (ii) design of non-conventional tests, possibly integrated with full field measurements and advanced modelling; (iii) the synthesis of meta-materials, namely the identification of the microstructures which fit a target behaviour at the macroscale. The scientific literature on generalized elastic media, with the focus on the higher gradient models, is fathomed in search of questions and methods which are typical of inverse problems theory and issues related to parameter estimation, providing hints and perspectives for future research.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1413 - 1453"},"PeriodicalIF":1.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00161-024-01314-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141895360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"New approach to ({upalpha })-titanium mechanical properties enhancement by means of thermoplastic deformation in mid-temperature range","authors":"Jakub Bańczerowski,&nbsp;Marek Pawlikowski,&nbsp;Tomasz Płociński,&nbsp;Andrzej Zagórski,&nbsp;Sylwester Sawicki,&nbsp;Roman Gieleta","doi":"10.1007/s00161-024-01321-4","DOIUrl":"10.1007/s00161-024-01321-4","url":null,"abstract":"<div><p>Pure titanium due to its high corrosion resistance, low stiffness and good mechanical properties is commonly used in medicine for orthopaedic applications. However, its material properties (especially in the case of <span>({upalpha })</span>-titanium) require a further enhancement to fulfil its role. The thermoplastic deformation in mid-temperature is proposed as a method for microstructure improvement. Titanium samples were compressed in different temperatures and strain rates to determine the best conditions for grain fragmentation—the main factor responsible for strength and hardness increase. The thermoplastic stress–strain curves were registered. Then microstructure observations and electron backscatter analysis were performed on the chosen samples. Finally, mechanical response of the previously deformed material was obtained in room temperature compression tests. A significant grain fragmentation was recorded for the material deformed in 400 <span>(^{circ }hbox {C})</span>, at 0.1/s and 1/s strain rates. Desirable results were also noticed for the deformation performed at 500–600 <span>(^{circ }hbox {C})</span>. However, high temperatures (700–800 <span>(^{circ }hbox {C})</span>) and strain rates (10/s) resulted in dynamic recrystallization, causing undesirable grain growth. An increase in hardness was observed in all cases, with higher values recorded in lower deformation temperatures. Room temperature compression tests revealed slight increase of ductility.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1645 - 1660"},"PeriodicalIF":1.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00161-024-01321-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141895356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Thermo-oxidative aging of natural rubber: experimental study and a thermodynamically consistent mechanical-chemical-diffusion model","authors":"A. Jalalpour,&nbsp;J. Arghavani,&nbsp;R. Naghdabadi","doi":"10.1007/s00161-024-01317-0","DOIUrl":"10.1007/s00161-024-01317-0","url":null,"abstract":"<div><p>Elastomers have diverse properties that make them suitable for use in many industrial applications. Natural Rubber, in particular, is an attractive elastomer due to its desirable mechanical properties as well as lightweight compared to metals. However, due to the natural rubber structure, these elastomers are susceptible to heat, oxidation, and chemical compounds, which limits their potential use. In this paper, in order to study the behavior of natural rubber under thermo-oxidative aging, experiments, including continuous stress relaxation, creep, and intermittent tensile tests, are carried out on the samples. Based on the experimental results and using dynamic-network model, a mechanical-chemical-diffusion model is proposed to predict the changes in natural rubber properties during thermo-oxidative aging considering the effect of the natural rubber curing system. In the chemical part of the model, the two main process of aging, including chain scission and crosslinking, are modeled by using two internal variables. The proposed model is implemented using the finite element method to simulate experimental tests for the model verification. The comparisons demonstrate the proposed model ability to accurately simulate the various loading states under thermo-oxidative aging of natural rubber.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1579 - 1595"},"PeriodicalIF":1.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141891829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From approximation of dissipative systems to representative space-time volume elements for metamaterials","authors":"Olga Chekeres,&nbsp;Vladimir Salnikov,&nbsp;Francesco D’Annibale","doi":"10.1007/s00161-024-01318-z","DOIUrl":"10.1007/s00161-024-01318-z","url":null,"abstract":"<div><p>In this paper we present some relatively unexpected mathematical questions emerging from the idea to approximate dissipative mechanical systems using Lagrangian formalism. We also explain potential consequences of these constructions for definition of representative space-time volume elements in modelling of metamaterials.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1597 - 1605"},"PeriodicalIF":1.9,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface layer effect on high pressure phase growth in a bicrystal: phase field model and simulations","authors":"Seyed Hamed Mirmahdi,&nbsp;Mahdi Javanbakht,&nbsp;Emilio Barchiesi","doi":"10.1007/s00161-024-01316-1","DOIUrl":"10.1007/s00161-024-01316-1","url":null,"abstract":"<div><p>Effect of the external surface layer on the phase transition (PT) between the low pressure phase and high pressure phase (HPP) in a NiAl bicrystal is investigated. Using a phase field model, the external surface layer is included, within which the elastic properties and surface energy are properly distributed. After resolving a stationary layer, the coupled phase field and elasticity equations are solved to capture the HPP evolution. Residual stress concentrator is included as a shear band representing an inelastic shear strain. Due to the small grain size, the surface layer can influence the stress distribution and consequently, the critical inelastic shear strain <span>(gamma _{cr})</span> for the HPP growth. Above a certain applied pressure, the surface layer width <span>({Delta }_{{xi }})</span> shows no effect on <span>(gamma _{cr})</span>, e.g., <span>(P=10)</span> GPa for the grain size of L <span>(=)</span> 20 nm. For lower pressures, <span>(gamma _{cr})</span> increases as pressure reduces. Due to the interplay of size addition by the surface layer and size reduction by the transformation strain, <span>(gamma _{cr})</span> reduces versus <span>({Delta }_{{xi }})</span> and then increases for larger <span>({Delta }_{{xi }})</span>. For smaller grain sizes, the surface layer effect is promoted as it is imposed to a larger transformation work. The lowest <span>(gamma _{cr})</span> is obtained for <span>(P=19)</span> GPa, in good agreement with the theoretical pressure of 20 GPa. Combining the external shear on pressure adds an extra shear term to the transformation work, which allows for the relaxation of the shear band and results in a nonlinear reduction of the PT pressure versus applied shear.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1565 - 1577"},"PeriodicalIF":1.9,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141755071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}