Continuum Mechanics and Thermodynamics最新文献

{"title":"A semi-analytical approach for thermoelastic wave propagation in infinite solids subject to linear heat supply using two-phase lag theory","authors":"Ahmed E. Abouelregal,&nbsp;Fahad Alsharari,&nbsp;S. S. Alsaeed,&nbsp;Mohammed Aldandani,&nbsp;Hamid M. Sedighi","doi":"10.1007/s00161-024-01324-1","DOIUrl":"10.1007/s00161-024-01324-1","url":null,"abstract":"<div><p>This study examines how heat travels as thermoelastic waves in a uniform, isotropic, and infinitely large solid material due to a constant line heat source. We leverage the theory of thermoelasticity with two phase lags to account for the time difference between temperature changes and the material’s stress response. By employing a potential function approach alongside Laplace and Hankel transforms, we can convert the governing equations into more manageable domains. This enables us to derive mathematical formulas for temperature, displacement, and stress distributions within the solid. Through a complex inversion process of the Laplace transforms, we obtain analytical formulas for these field distributions. These formulas, however, are only valid for short time periods and are most applicable in the initial stages of wave propagation. We then use these analytical formulas to visualize how temperature, displacement, and stress are distributed, revealing the influence of the heat source and phase lag parameters on these fields. This approach provides valuable insights into the characteristics of wave propagation, the heat source’s impact, and the time-dependent nature of the thermoelastic response. Furthermore, to demonstrate the method’s versatility and ability to connect with established theories, we incorporate specific examples from other thermoelasticity theories. This broadens our understanding of thermoelastic behavior under various conditions.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1711 - 1728"},"PeriodicalIF":1.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235251","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":"Complex mechanical properties of 3D micro-metric pantographic metamaterials fabricated by two-photon polymerization","authors":"Emilio Barchiesi,&nbsp;Stefanos Mavrikos,&nbsp;Ivan Giorgio,&nbsp;Costas Grigoropoulos,&nbsp;Maria Farsari,&nbsp;Francesco dell’Isola,&nbsp;Gordon Zyla","doi":"10.1007/s00161-024-01327-y","DOIUrl":"10.1007/s00161-024-01327-y","url":null,"abstract":"<div><p>Mechanical metamaterials consist of specially engineered features designed to tailor and enhance the mechanical properties of their constituent materials. In this context, 2D pantographic fabrics have gained attention for their unique deformation behavior, providing remarkable resilience and damage tolerance. This study explores micro-metric metamaterials with 3D pantographic motifs, aiming to transfer these properties to small scales. 3D micro-metric structures were designed using 2D pantographic fabrics arranged in multiple layers, each featuring unit cells with quasi-perfect pivots. Relatively large specimens of 3D micro-metric pantographs, measuring 158 <span>(upmu )</span>m x 250 <span>(upmu )</span>m x 450 <span>(upmu )</span>m, were fabricated in various configurations using two-photon polymerization. These specimens were mechanically characterized through in-situ scanning electron microscopy microindentation under conditions of cyclic deformation. Structural failures were subsequently assessed via helium-ion microscopy. The 3D micro-metric pantographs exhibited complex mechanical properties, some aligning with those of 2D pantographic fabrics, while new properties, such as a dissipative response and softening, were identified. Nonetheless, the 3D micro-metric pantographs demonstrated great resilience against deformation and enhanced resistance to undesired out-of-plane motions, indicating their potential for novel applications in advanced engineering fields. Additionally, the findings can potentially lead to optimizing and enriching theoretical models describing the mechanical behavior of pantographic metamaterials.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1755 - 1766"},"PeriodicalIF":1.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142234194","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":"On the influence of microproperties of elastoplastic hinges on the global behavior of pantographic sheets in bias extensional test","authors":"G. La Valle,&nbsp;F. Fabbrocino,&nbsp;B. Desmorat","doi":"10.1007/s00161-024-01325-0","DOIUrl":"10.1007/s00161-024-01325-0","url":null,"abstract":"<div><p>Experimental observations have revealed a change in the concavity of the resultant force-displacement plot in the extension test for pantographic sheets. In this paper, we aim to relate these macroscopically observed mechanical properties with the microscale properties of the hinges (or pivots) connecting the pantographic fibers. The material constituting the hinges is modeled at the microscale as an isotropic elastoplastic 3D Cauchy continuum. The elastic regime is assumed to be linear, while the plastic regime exhibits either saturating or non-saturating hardening. In the case of circular homogeneous cylindrical hinges, monotonic loading is considered to derive a mesoscale constitutive relation linking the torsional angle to the total applied torque. It is demonstrated that (non-)saturating hardening at the microscale results in (non-)saturating hardening of the twist angle/torque plot at the mesoscale, which itself is responsible for the change of concavity in bias extensional test of pantographic sheets.</p></div>","PeriodicalId":525,"journal":{"name":"Continuum Mechanics and Thermodynamics","volume":"36 6","pages":"1729 - 1740"},"PeriodicalIF":1.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142160704","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":"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}