International Journal of Mechanical Sciences最新文献

{"title":"Unsupervised transfer learning for monitoring CFRP responses using discrete strains","authors":"Huai Yan,&nbsp;Songhe Meng,&nbsp;Bo Gao,&nbsp;Fan Yang,&nbsp;Weihua Xie","doi":"10.1016/j.ijmecsci.2025.110142","DOIUrl":"10.1016/j.ijmecsci.2025.110142","url":null,"abstract":"<div><div>A deep learning (DL) model based on an unsupervised domain adaptation (UDA) approach is developed to learn shared features from labeled simulation datasets and transfer them to unlabeled experimental data for predicting CFRP displacement response and delamination growth. Different from traditional transfer learning methods based on fine-tuning strategies, the UDA-DL model focuses on the unlabeled target domain, aiming to learn prior knowledge in the source domain data for transfer. Specifically, a DL model with an encoder-decoder architecture is first built to construct an inverse mapping between discrete strains and displacement responses. The model is verified to efficiently and accurately predict the displacement field based on strains. Furthermore, the impact of the number of strain points and data type on the prediction of the out-of-plane displacement field is discussed. Subsequently, the UDA strategy is introduced into the DL model, which realizes the transfer of simulated data to experimental data based on shared features extracted by domain separation. The comparison with experimental results confirms the potential of the UDA-DL model in the prediction of displacement fields and delamination growth. This study provides a promising solution to the challenge of state sensing with unlabeled monitoring data in structural health monitoring.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110142"},"PeriodicalIF":7.1,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indentation of freestanding pre-stressed films: Extracting elastic modulus and pre-tension, elucidating finite-sized indenter effect","authors":"Shuyi Xiang ,&nbsp;Longkun Lu ,&nbsp;Zhibo Du ,&nbsp;Kaijie Wang ,&nbsp;Zhanli Liu","doi":"10.1016/j.ijmecsci.2025.110141","DOIUrl":"10.1016/j.ijmecsci.2025.110141","url":null,"abstract":"<div><div>The indentation test is an important method for characterizing the mechanical properties of solid films. However, how to extract the elastic modulus of pre-stressed circular films through the indentation test is still debatable due to the transition between linear membrane, nonlinear membrane, and plate behavior. This study proposes a method for extracting elastic modulus and pre-tension of freestanding film simultaneously by integrating an indentation test and theoretical modeling. Firstly, we introduce the experimental setting and results of polydimethylsiloxane (PDMS) films. The theoretical model for the cylindrical indentation of freestanding circular film is then presented, considering the combined contribution of pre-tension, additional stretching, and bending stiffness to mechanical response. After that, the elastic modulus and pre-tension are extracted by iteratively solving the full governing equations until the difference between numerical and experimental load-deflection curves is minimized. The asymptotic results derived from the full governing equations are compared with classical asymptotic solutions in the linear membrane, nonlinear membrane, and plate regimes to verify the theoretical modeling. Finally, the explicit indentation force-depth formula for the finite-sized indenter is proposed. The underlying mechanism of the synergistic effect of pre-tension, additional stretching and bending stiffness on indentation behavior in the transition region is elucidated.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110141"},"PeriodicalIF":7.1,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite deformations induce friction hysteresis in normal wavy contacts","authors":"M. Ceglie,&nbsp;G. Violano,&nbsp;L. Afferrante,&nbsp;N. Menga","doi":"10.1016/j.ijmecsci.2025.110115","DOIUrl":"10.1016/j.ijmecsci.2025.110115","url":null,"abstract":"<div><div>Since Hertz’s pioneering work in 1882, contact mechanics has traditionally been grounded in linear elasticity, assuming small strains and displacements. However, recent experiments clearly highlighted linear elasticity limitations in accurately predicting the contact behavior of rubbers and elastomers, particularly during frictional slip, which is governed by geometric and material nonlinearity.</div><div>In this study, we investigate the basic scenario involving normal approach-retraction contact cycles between a wavy rigid indenter and a flat, deformable substrate. Both frictionless and frictional interfacial conditions are examined, considering finite strains, displacements, and nonlinear rheology. We developed a finite element model for this purpose and compared our numerical results with Westergaard’s linear theory.</div><div>Our findings show that, even in frictionless conditions, the contact response is significantly influenced by geometric and material nonlinearity, particularly for wavy indenters with high aspect ratios, where normal-tangential stresses and displacements coupling emerges. More importantly, interfacial friction in nonlinear elasticity leads to contact hysteresis (i.e., frictional energy dissipation) during normal loading–unloading cycles. This behavior cannot be explained in a linear framework; therefore, most of the experiments reporting hysteresis are typically explained invoking other interfacial phenomena (e.g., adhesion, plasticity, or viscoelasticity). Here we present an additional suitable explanation relying on finite strains/displacements with detailed peculiarities, such as vanishing pull-off force. Moreover, we also report an increase of hysteretic losses as for confined systems, stemming from the enhanced normal-tangential nonlinear coupling.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110115"},"PeriodicalIF":7.1,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design strategy of curved-beam based metamaterial with unprecedented lateral deformation mode transition","authors":"Jinyu Ji ,&nbsp;Kai Zhang ,&nbsp;Xiaogang Guo ,&nbsp;Daining Fang","doi":"10.1016/j.ijmecsci.2025.110136","DOIUrl":"10.1016/j.ijmecsci.2025.110136","url":null,"abstract":"<div><div>Mechanical metamaterials exhibiting unconventional Poisson's ratios hold significant promise for applications in flexible electronics, impact protection, medical devices, and shape-shifting structures. However, achieving complex Poisson's ratio behaviors—particularly nonlinear and directional-switching responses under large deformations—remains a considerable challenge. This study introduces a class of variable-thickness curved-beam metamaterials (VCBMs) capable of exhibiting intricate nonlinear lateral displacement responses, including direction-reversing behaviors, under large tensile strains. To enable the customizable design of VCBM unit cells with complex Poisson's ratio profiles, an inverse design framework integrating neural networks (NN) and particle swarm optimization (PSO) is proposed. This framework facilitates the precise tailoring of VCBM unit cells with nonlinear, sign-switching force-lateral displacement curves and enables the development of spatially heterogeneous metamaterials with unprecedented lateral deformation transitions. As a case study, the framework is applied to create metamaterials that transition from a flat configuration to a dumbbell shape and subsequently to a vase-like form under uniaxial stretching. Both numerical simulations and experimental validations confirm the effectiveness of this approach, highlighting the unprecedented lateral displacement mode transitions under tensile loading. The proposed methodology lays the foundation for developing advanced reconfigurable metamaterials with versatile applications in mechanical systems, soft robotics, programmable materials, and medical devices.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110136"},"PeriodicalIF":7.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 physics-informed neural network-based method for dispersion calculations","authors":"Zhibao Cheng ,&nbsp;Tianxiang Yu ,&nbsp;Gaofeng Jia ,&nbsp;Zhifei Shi","doi":"10.1016/j.ijmecsci.2025.110111","DOIUrl":"10.1016/j.ijmecsci.2025.110111","url":null,"abstract":"<div><div>The study of dispersion relations of periodic structures or elastic metamaterials is essential to understand and optimize their unique wave propagation characteristics. By integrating physical laws for the generation of physically consistent results without labeled data, Physics-Informed Neural Networks (PINNs) offer a new perspective on scientific computation, which is a potential machine learning method in advancing the analysis and design of advanced materials. In this study, we introduce a novel PINN-based numerical method for the calculation of dispersion calculations of periodic structures. First, coupling the physical information of the dispersion problem of periodic structures and the neural networks PDE solver, the framework of the proposed method is constructed. Unlike those existing PINNs, the proposed PINN is designed for the first time to handle the dispersion problem as well as the equivalent eigenvalue problem. In particular, a unified framework is proposed to solve both the real and complex eigenvalue problems, from which the real and complex dispersion curves of periodic structures are obtained. Second, comparing with the analytical results, the correctness of the proposed method is validated. And, dispersion properties for propagative waves in pass bands and evanescent waves in stop bands are analyzed. Third, a comprehensive analysis of the convergence of the proposed method is performed. The Neural Tangent Kernel (NTK)-based adaptive loss weighting scheme is integrated into the proposed PINN to achieve the balanced convergence across different loss terms. Meanwhile, the Random Fourier Feature Mapping is implemented into the proposed method to mitigate the eigenfrequency bias problem. Comparison results demonstrate that such enhancements allow for a more accurate convergence. For the considered dispersion problem, a coherent convergence is achieved for all eigenfrequencies in the desired frequency range. In summary, the proposed physics-informed machine learning method is a promising computational method for the dispersion problem of periodic structures.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110111"},"PeriodicalIF":7.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of elastoviscoplastic polymer flows in material extrusion additive manufacturing","authors":"Haifeng Zhang ,&nbsp;Dongjie Liu ,&nbsp;Fei Chen ,&nbsp;Wenjun Yuan ,&nbsp;Wentao Yan","doi":"10.1016/j.ijmecsci.2025.110139","DOIUrl":"10.1016/j.ijmecsci.2025.110139","url":null,"abstract":"<div><div>Understanding the coupled effects of elasticity and plasticity in polymeric inks is crucial for improving strand quality and residual stress management in material extrusion (MEX) additive manufacturing (AM). However, these effects have been overlooked in existing studies. In this work, the Saramito model is employed to characterize the complex rheological properties of elastoviscoplastic (EVP) inks in extrusion and deposition. Parametric studies are conducted by varying the Bingham number (<em>Bi</em>), Weissenberg number (<em>Wi</em>), and the ratio of printing speed to extrusion speed (<em>v</em>/u). Results identify four distinct printing modes and reveal that high <em>Bi</em> leads to poor printing quality at non-optimal <em>Wi</em> and <em>v</em>/u. Additionally, an unbalanced distribution of residual stress is observed in the strand at higher <em>Bi</em>, and the shape of strands tends to be unsmooth. The normalized height (<em>H</em>/<em>D</em>) of the stable area decreases with an increase in <em>Wi</em>, while the normalized width (W/<em>D</em>) shows the opposite trend. Furthermore, the unyielded area and the distribution of residual stress inside strands show that the dominant mechanism transitions from plasticity and elasticity as <em>Bi</em> increases. The larger <em>v</em>/u leads to an elongated shape of the stable area, and an obvious neck appears between the head and the stable area. This work contributes to the understanding of plastic deformation of complex polymers in various flow states, thereby providing valuable guidance to MEX-AM.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110139"},"PeriodicalIF":7.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 vibro-acoustic coupling modeling method for coplanar built-up plates","authors":"Xinxin Wang,&nbsp;Tiangui Ye,&nbsp;Guoyong Jin,&nbsp;Yukun Chen,&nbsp;Zhigang Liu","doi":"10.1016/j.ijmecsci.2025.110140","DOIUrl":"10.1016/j.ijmecsci.2025.110140","url":null,"abstract":"<div><div>Coplanar built-up plates coupled by plate elements have wide applicability in engineering fields. Their diverse geometries pose a challenge to vibro-acoustic coupling modeling. Therefore, a discrete collocation point method is proposed for the first time to establish a semi-analytical vibro-acoustic coupling model for such structures. Based on the infinitely rigid baffle assumption, one side of coplanar built-up plates is in contact with a semi-infinite heavy fluid domain. Motivated by the element discretization, the coplanar built-up plates are discretized into several elements, the boundary conditions and coupling conditions are implemented using virtual springs. All energy expressions are derived via the first-order shear deformation theory. When considering the sound pressure loading effect, the vibration and acoustic fields of each element are expanded in Chebyshev polynomials. Relying on sound pressure continuity, the vibro-acoustic coupling relationships among the elements are established. Finally, a complete vibro-acoustic coupling equation is derived using the Rayleigh-Ritz method. This paper takes cross-shaped, T-shaped, Z-shaped and L-shaped built-up plates as examples to validate the convergence and accuracy of the proposed method. Furthermore, the underwater vibro-acoustic characteristics of the above-mentioned structures are analyzed. This work is expected to be a valuable and dependable reference for future research of such structures.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110140"},"PeriodicalIF":7.1,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generative deep learning for designing irregular metamaterials with programmable nonlinear mechanical responses","authors":"Zhuoyi Wei ,&nbsp;Jiaxin Chen ,&nbsp;Kai Wei","doi":"10.1016/j.ijmecsci.2025.110123","DOIUrl":"10.1016/j.ijmecsci.2025.110123","url":null,"abstract":"<div><div>Introducing irregularities found in natural materials enables metamaterials to achieve excellent properties or special functions, while it still poses challenges in customizing their nonlinear responses due to the huge design space and complex intrinsic structure-property relationships. Here, we originally propose a generative deep learning framework, which synergistically comprises a variational encoder and a property predictor, to construct a continuous and meaningful latent space for designing irregular metamaterials with programmable strain-stress curves. Specifically, irregular metamaterials are created through two types of building blocks with opposite deformation directions, and thus rich stress-strain curve responses are achieved benefitting from their different spatial arrangements. Furthermore, we obtain new irregular metamaterials beyond the dataset by simple manipulations in the latent space. Finally, we deploy an optimization method to flexibly achieve the inverse design of irregular metamaterials to satisfy targeted strain-stress curves. Particularly, we successfully identify multiple irregular metamaterials hitting the same nonlinear properties. Our established framework provides a new approach to meet prescribed yet complex nonlinear mechanical behavior and contributes to deep learning-aided materials design.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110123"},"PeriodicalIF":7.1,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Positive and negative feedback of entangled lightning multiphysics on composites","authors":"Yue Wu ,&nbsp;Fusheng Wang ,&nbsp;Chenyang Lv ,&nbsp;Jinru Sun ,&nbsp;Xiangteng Ma ,&nbsp;Chenguang Huang ,&nbsp;Zhiqiang Fan ,&nbsp;Shaozhen Wang ,&nbsp;Chenglin Wang ,&nbsp;Yunpeng Gao ,&nbsp;Zemin Duan ,&nbsp;Xueling Yao","doi":"10.1016/j.ijmecsci.2025.110022","DOIUrl":"10.1016/j.ijmecsci.2025.110022","url":null,"abstract":"<div><div>Lightning strike will have intertwined multi-physical effects on carbon fiber reinforced polymer. According to experiments and high-fidelity simulations in this study, distinctive positive and negative feedback is originally identified between the entangled lightning effects in composites damage driving. The intricate mesoscopic feedback mechanisms are groundbreakingly revealed through the anisotropic equivalent circuit. Positive feedback exists between ablation and mechanical effects, while thermal strain is counteracted by overpressure and ampere force effects. These feedback relationships are formed due to dissimilar action mechanisms and energy transformations, which dynamically change with time and location. They jointly cause complex non-uniform damage to composites.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"290 ","pages":"Article 110022"},"PeriodicalIF":7.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Closed-form solutions for wave propagation in hexagonal diatomic non-local lattices","authors":"F. Ongaro ,&nbsp;P.H. Beoletto ,&nbsp;F. Bosia ,&nbsp;M. Miniaci ,&nbsp;N.M. Pugno","doi":"10.1016/j.ijmecsci.2025.110095","DOIUrl":"10.1016/j.ijmecsci.2025.110095","url":null,"abstract":"<div><div>Periodic mass–spring lattices are commonly used to investigate the propagation of waves in elastic systems, including wave localisation and topological protection in phononic crystals and metamaterials. Recent studies have shown that introducing non-neighbouring (i.e., beyond nearest neighbour) connections in these chains leads to multiple topologically localised modes, while generating roton-like dispersion relations. This paper focuses on the theoretical analysis of elastic wave propagation in hexagonal diatom mass–spring systems in which both neighbouring and non-neighbouring interactions occur through linear elastic springs. Closed-form expression for the dispersion equations are derived, up to an arbitrary order of beyond-the-nearest connections for both in-plane and out-of-plane mass displacements. This allows to explicitly determine the influence of the order of non-neighbouring interactions on the band gaps, the local minima and the slope inversions in the first Brillouin zone for the considered unit cell. All analytical solutions are numerically verified. Finally, examples are provided on how non-neighbouring connections can be exploited to enhance the localisation of topologically-protected edge modes in waveguides constructed using mirror symmetric diatomic lattices constituted by two regions with different unit cell orientations. The study provides further insight on how to design phononic crystals generating roton-like behaviour and to exploit them for topologically protected waveguiding.</div></div>","PeriodicalId":56287,"journal":{"name":"International Journal of Mechanical Sciences","volume":"291 ","pages":"Article 110095"},"PeriodicalIF":7.1,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}