International Journal of Non-Linear Mechanics最新文献

{"title":"Multiscale and microstructure-inspired constitutive models for soft materials. On the occasion of Giuseppe Saccomandi's 60th birthday","authors":"Michel Destrade, Giuseppe Puglisi, Ivonne Sgura","doi":"10.1016/j.ijnonlinmec.2024.104865","DOIUrl":"10.1016/j.ijnonlinmec.2024.104865","url":null,"abstract":"","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104865"},"PeriodicalIF":2.8,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive analysis of electro-mechanical characteristics and new regression models of a novel slanted groove electrical connector","authors":"Bo Qin ,&nbsp;Ying Zhang","doi":"10.1016/j.ijnonlinmec.2024.104863","DOIUrl":"10.1016/j.ijnonlinmec.2024.104863","url":null,"abstract":"<div><p>Electrical connectors are crucial electro-mechanical components, with insertion, withdrawal, and electrical contact characteristics serving as key indicators of their reliability. Studying the electro-mechanical characteristics and regression models of electrical connectors is vital to enhance their reliability. This work focuses on the M2-type electrical connector, investigating its electro-mechanical characteristics and developing a regression model. A withdrawal force calculation model is established using cantilever beam theory. Simulation and analysis provide data on insertion force, contact pressure, and contact resistance. Experiments on insertion, withdrawal, and electrical contact are conducted using an insertion force tester and a DC low-resistance instrument, comparing experimental results with simulations. The study reveals the fitting relationship between contact pressure and contact resistance for the M2-type connector. Key findings include a stable fluctuation in contact pressure with a relative error of 1.72% between simulated and tested values, an average discrepancy of 3.81% for insertion force, and 2.38% for withdrawal force, with insertion force slightly higher than withdrawal force. Contact resistance shows a U-shaped trend with pin displacement, with an average experimental error 3.70% and 1.16% lower than theoretical values (4.86%). The new regression model (quadratic polynomial fitting) demonstrates mean absolute percentage errors of 0.1458% for simulation values and 0.2219% for experimental values, significantly lower than those obtained using theoretical formulas (0.7046% and 0.3451%). These results provide theoretical guidance for studying electro-mechanical characteristics and designing experiments for electrical connectors, offering valuable insights for designing and ensuring the reliability of new types of electrical connectors.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104863"},"PeriodicalIF":2.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postbuckling and nonlinear free vibration of postbuckled porous functionally graded micro/nanotubes via nonlocal strain and velocity gradient theory","authors":"S. Ziaee","doi":"10.1016/j.ijnonlinmec.2024.104862","DOIUrl":"10.1016/j.ijnonlinmec.2024.104862","url":null,"abstract":"<div><h3>Background</h3><p>Vibration response analysis serves as a critical tool in investigating the behavior of micro/nanoscale structures operating in dynamic environments, offering valuable insights into their performance and ultimately refining the design of devices. Particularly, when these structures are deliberately engineered to function near or within the postbuckling regime, understanding their vibratory behavior in this state becomes essential. This study focuses on exploring the postbuckling behavior and nonlinear frequencies of simply supported buckled porous functionally graded (PFG) size-dependent tubes. Internal resonances are not considered in this analysis.</p></div><div><h3>Method</h3><p>The nonlocal strain and velocity gradient theory, within the framework of the Euler-Bernoulli beam hypothesis, is employed to derive the nonlinear partial differential equations of motion. It is assumed that the material properties are gradually graded in the radial direction. Additionally, two different porosity distribution patterns are used in the radial direction. The method of multiple scales is used to solve the system of nonlinear ordinary differential equations obtained by applying the Galerkin method.</p></div><div><h3>Results</h3><p>The closed expression for the i-th nonlinear frequency of buckled porous functionally graded size-dependent tubes is determined based on the amplitude of the vibration modes involved. The findings indicate that porous M/NTs exhibit a loss of static stability at lower compressive axial loads compared to their nonporous counterparts. Furthermore, the softening effects resulting from a uniform porosity distribution are more pronounced than those from an uneven porosity distribution. Interestingly, nonporous M/NTs display the lowest nonlinear postbuckling frequency among the studied configurations. Moreover, it is observed that the nonlinear frequency tends to increase with a rise in the compressive axial load, while it decreases with an increase in the excitation amplitude.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104862"},"PeriodicalIF":2.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Periodic response and stability analysis of a bistable viscoelastic von Mises truss","authors":"Pritam Ghoshal ,&nbsp;James M. Gibert ,&nbsp;Anil K. Bajaj","doi":"10.1016/j.ijnonlinmec.2024.104858","DOIUrl":"10.1016/j.ijnonlinmec.2024.104858","url":null,"abstract":"<div><p>This paper examines the effect of viscoelasticity on the periodic response of a lumped parameter viscoelastic von Mises truss. The viscoelastic system is described by a second-order equation that governs the mechanical motion coupled to a first-order equation that governs the time evolution of the viscoelastic forces. The viscoelastic force evolves at a much slower rate than the elastic oscillations in the system. This adds additional time scales and degrees of freedom to the system compared to its viscous counterparts. The focus of this study is on the system’s behavior under harmonic loading, which is expected to show both regular and chaotic dynamics for certain combinations of forcing frequency and amplitude. While the presence of chaos in this system has already been demonstrated, we shall concentrate only on the periodic solutions. The presence of the intrawell and interwell periodic oscillations is revealed using the Harmonic Balance method. The study also looks at the influence of parameter changes on the system’s behavior through bifurcation diagrams, which enable us to identify optimal system parameters for maximum energy dissipation. Lastly, we formulate an equivalent viscous system using an energy-based approach. We observe that a naive viscous model fails to capture the behavior accurately depending on the system and excitation parameters, as well as the type of excitation. This underscores the necessity to study the full-scale viscoelastic system.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104858"},"PeriodicalIF":2.8,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141935368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning prediction models for investigating vibration properties of epoxy resin under moisture conditions","authors":"Guoqiang Cai ,&nbsp;Dehan Zhang ,&nbsp;Jia-ao Hou ,&nbsp;Denvid Lau ,&nbsp;Renyuan Qin ,&nbsp;Wenhao Wang ,&nbsp;W. Zhang ,&nbsp;Chao Wu ,&nbsp;Lik-ho Tam","doi":"10.1016/j.ijnonlinmec.2024.104857","DOIUrl":"10.1016/j.ijnonlinmec.2024.104857","url":null,"abstract":"<div><p>Epoxy resins used in engineering applications are commonly exposed to wet environment during intended service life, which causes vibration property degradation and increasing risk of structural failure. In this work, vibration properties of epoxy resin plate under different moisture conditions are predicted with various sizes and boundary conditions using developed machine learning (ML) models. The dataset of epoxy vibration is established first, where values in the dataset are calculated with five moisture contents using previously developed meshless model. The dataset from meshless simulation is used to train ML models of epoxy vibration using six different algorithms, including support vector machine, decision tree, random forest, gradient boosting decision tree, extreme gradient boosting, and artificial neural network. It is found that the prediction model developed using extreme gradient boosting algorithm shows the highest accuracy of 99.9% and strong reliability. Using this model, vibration properties of epoxy resin with a series of sizes and boundary conditions are predicted under various moisture contents from dry case to saturated case, which deepens the understanding of the effects of wet environments on the vibration responses of epoxy resins. The results could be used for analysis of durability of epoxy resin, and the developed ML prediction models contribute to investigating vibration property of epoxy resin under different moisture conditions, which is crucial for ensuring durability of epoxy resin in wet environment.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104857"},"PeriodicalIF":2.8,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141838754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear dynamics of a dual-rotor system with active elastic support/dry friction dampers based on complex nonlinear modes","authors":"Xu Ouyang ,&nbsp;Shuqian Cao ,&nbsp;Yuanhang Hou ,&nbsp;Guanwu Li ,&nbsp;Xin Huang","doi":"10.1016/j.ijnonlinmec.2024.104856","DOIUrl":"10.1016/j.ijnonlinmec.2024.104856","url":null,"abstract":"<div><p>In this study, the nonlinear dynamics of a dual-rotor system with active elastic support/dry friction dampers (ESDFDs) are investigated based on complex nonlinear modes (CNMs). The finite element method (FEM) combined with a full-3D friction model is introduced to construct the governing equation for the system. Additionally, the Craig–Bampton technique is applied to downscale the finite element model of the system. Based on the reduced order model (ROM), the nonlinear modal damping ratio of the target mode is employed to measure the dry friction damping performance of active ESDFD. The effects of the active ESDFD position, normal force, and tangential contact stiffness on the nonlinear modal damping ratio and modal frequency are analysed. Moreover, the softening characteristics of the active ESDFD are revealed, and the critical speed intervals of the active ESDFD/dual-rotor system are determined. Furthermore, by using the harmonic balance–alternating frequency/time domain (HB–AFT) method, the steady-state response of the system under unbalanced excitation is calculated. The accuracy and effectiveness of nonlinear modal analysis are validated based on the relationships between nonlinear modes and steady-state unbalanced responses. Conversely, the vibration mitigation effects of active ESDFD are determined by the unbalanced response amplitude. Additionally, the controllable region and optimal normal force for effective vibration control in the target mode are defined. Depending on the controllable region, a control strategy for turning on/off the optimal normal force is developed. The findings demonstrate that the developed control strategy enables the active ESDFD to significantly reduce the response amplitude of the dual-rotor system across various excitation levels, showing substantial potential for engineering applications.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104856"},"PeriodicalIF":2.8,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141848442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 note on longitudinal and torsional oscillations of a rod in a generalized non-Newtonian fluid","authors":"L. Fusi ,&nbsp;A. Farina ,&nbsp;K.R. Rajagopal","doi":"10.1016/j.ijnonlinmec.2024.104836","DOIUrl":"10.1016/j.ijnonlinmec.2024.104836","url":null,"abstract":"<div><p>The rotational and torsional oscillations of a rod in a fluid has relevance to several applications. Stokes recognized that the rotational oscillations in a Navier–Stokes fluid allows one to obtain an exact solution. This seminal work has been extended by Casarella and Laura to find an exact solution to both the rotational and torsional oscillations in a Navier–Stokes fluid. This work has been generalized to the case of several non-Newtonian fluids by subsequent authors. In this study we analyze the solution that corresponds to two classes of non-Newtonian fluids, the constitutive relation put forth by Carreau and Yasuda, and a relatively new constitutive relation due to Garimella et al. that mimics viscoplastic flow exhibited by many materials.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104836"},"PeriodicalIF":2.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Instability of single polymer chain in an electroelastic problem","authors":"Sugeng Waluyo","doi":"10.1016/j.ijnonlinmec.2024.104855","DOIUrl":"10.1016/j.ijnonlinmec.2024.104855","url":null,"abstract":"<div><p>Under electric loading produced by compliant electrodes, a dielectric elastomer is prone to material instabilities which, in a microstructural level, may connect to single polymer chain instability. To reveal if such connection exists, we aim to use an electroelastic energy model for single polymer chain to study the chain instability. We approximate curvature shape of the chain under the electric loading by using trigonometry series in a spatial coordinate. The Rayleigh–Ritz method is then applied to solve the energy equation formed by the trigonometry series. We demonstrate in the numerical examples that the instability of the chain may occur at the value of electric field with corresponding configuration of the chain close to its full length.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104855"},"PeriodicalIF":2.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141851443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rapid computation of Hopf bifurcation points of continuous and discrete systems through minimization","authors":"Chein-Shan Liu ,&nbsp;Chih-Wen Chang","doi":"10.1016/j.ijnonlinmec.2024.104847","DOIUrl":"10.1016/j.ijnonlinmec.2024.104847","url":null,"abstract":"<div><p>For an autonomous nonlinear system, the Hopf bifurcation point along the equilibrium path is a critical feature that indicates whether the values of the parameters change from exhibiting fixed-point behavior to having a periodic orbit. To solve these problems, we developed a method of transforming an eigenvalue problem based on the Jacobian matrix at equilibrium into a minimization problem, enabling the rapid identification of a solution. Specifically, this generalized eigenvalue problem is solved by identifying the vector variable after reducing the number of eigenequations by one in the nonhomogeneous linear system. This can be achieved by normalizing the value of a selected nonzero component of the eigenvector and then moving the column containing this component to the other side of the equation. An appropriate merit function was established in terms of the Euclidean norm of the eigenequation, and this merit function was minimized using the golden section search algorithm to determine the eigenparameters of the bifurcation point. The accuracy of the method for identifying the parameter values and the corresponding imaginary eigenvalues at the Hopf bifurcation points was evaluated for numerous examples for both the continuous and discrete systems. The method was both fast and accurate. Moreover, its stability in the presence of noise was investigated, and the method was robust.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104847"},"PeriodicalIF":2.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comment on the paper: Dynamics of accelerating and decelerating flows: A boundary layer examination with non-similar approach and convective boundary condition, Mojeed T. Akolade, et al. International Journal of Nonlinear Mechanics 161 (2024) #104675.","authors":"Asterios Pantokratoras","doi":"10.1016/j.ijnonlinmec.2024.104852","DOIUrl":"10.1016/j.ijnonlinmec.2024.104852","url":null,"abstract":"<div><p>The aim of this comment is to point out three major errors in the paper Akolade et al. (2024).</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"166 ","pages":"Article 104852"},"PeriodicalIF":2.8,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}