International Journal of Non-Linear Mechanics最新文献

{"title":"Size-dependent nonlinear modal dynamics in MEMS micro rotors","authors":"Mayank Ahirwar,&nbsp;Barun Pratiher","doi":"10.1016/j.ijnonlinmec.2025.105115","DOIUrl":"10.1016/j.ijnonlinmec.2025.105115","url":null,"abstract":"<div><div>Micro-rotor-dynamic systems are vital for rotor-based MEMS technologies, encountering nonlinear dynamics and size-dependent effects due to their small-scale, challenging optimization efforts. This study introduces a novel mathematical model that effectively captures the nonlinear modal dynamics and size-dependent influences in micro rotor-dynamic systems. By employing a non-classical approach-specifically, strain gradient theory-size dependencies are incorporated into the model. The equations of motion is obtained using extended Hamilton’s principle, which is solved using a perturbation technique-method of multiple scales. Extensive numerical simulations and analytical techniques are utilized to explore size-dependent nonlinearities, focusing on dynamic responses, frequency spectra, and phase portraits. In addition to that, parametric analyses of disk location, spin speed, disk mass, and disk mass moment of inertia are conducted to assess their impacts on the modal behavior of micro-dynamic systems. The results are rigorously validated using the Runge–Kutta(4,5) method, ensuring precision and accuracy. This research significantly advances the understanding of nonlinear modal dynamics in micro-scale systems and provides valuable insights for optimizing the design of rotating MEMS devices, effectively addressing scaling challenges.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"176 ","pages":"Article 105115"},"PeriodicalIF":2.8,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904349","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":"Analysis of a nonlinear aeroelastic system with parametric uncertainties under dynamic stall condition","authors":"Sourabh kumar ,&nbsp;Dheeraj Tripathi ,&nbsp;J. Venkatramani ,&nbsp;Ankit Gupta","doi":"10.1016/j.ijnonlinmec.2025.105116","DOIUrl":"10.1016/j.ijnonlinmec.2025.105116","url":null,"abstract":"<div><div>In this study, we analyse the response characteristics of a pitch-plunge aeroelastic system subjected to dynamic stall under the influence of system parametric uncertainty. These uncertainties can be caused by a lack of understanding of the system’s parameters, modelling assumptions or system-specific noise. The accuracy and safety of the structure would be enhanced by a systematic assessment of these uncertainties and their impact on the system. In order to account for this, the inflow speed (<span><math><mi>U</mi></math></span>), plunge to pitch frequency ratio (<span><math><mover><mrow><mi>ω</mi></mrow><mo>¯</mo></mover></math></span>), pitch(<span><math><msub><mrow><mi>ζ</mi></mrow><mrow><mi>α</mi></mrow></msub></math></span>), and plunge (<span><math><msub><mrow><mi>ζ</mi></mrow><mrow><mi>ξ</mi></mrow></msub></math></span>) damping ratio are all assumed to be uncertain parameters in the present nonlinear aeroelastic system. The uncertain system parameters fluctuations are modelled using a Karhunen–Loeve Expansion formulation and the aerodynamic loads at high angles-of-attacks during stall flutter are calculated using the Leishman–Beddoes (LB) semi-empirical dynamic stall model. Next, the response dynamics of the system under stall flutter conditions, are systematically investigated under isolated cases of deterministic, uncertainties in system parameters and stochastic input flow conditions. First, we investigate the effects of uncertain parameters individually and collectively on system response and then investigate response dynamics due to the effects of uncertain parameters combined with stochastic input flow for different time scales. In order to investigate the effect of system uncertainties on system and stall flutter bifurcation behaviour, stochastic phenomenological bifurcation analysis, is performed by examining the joint probability density function of the response quantities. Shannon entropy measure is used to capture the bifurcation boundary involving a topological change in the j-pdf. It is demonstrated that a phenomenologically rich class of stochastic responses, such as burst type intermittency, on-off intermittency, random oscillations, etc., are observed that give rise to complex cyclic stresses and can be critical to structural health. Importantly, we examine the occurrence of stall flutter events under parametric uncertainty, and fluctuating flow conditions and compare it with deterministic conditions. Finally, the associated fatigue damage is systematically investigated under uncertain parameters and fluctuating oncoming flow conditions.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105116"},"PeriodicalIF":2.8,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868974","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":"Effect of oblique horizontal magnetic field on convection rolls","authors":"Snehashish Sarkar ,&nbsp;Sutapa Mandal ,&nbsp;Pinaki Pal","doi":"10.1016/j.ijnonlinmec.2025.105111","DOIUrl":"10.1016/j.ijnonlinmec.2025.105111","url":null,"abstract":"&lt;div&gt;&lt;div&gt;We investigate the effect of external horizontal magnetic field applied on the convection rolls obliquely (at an angle &lt;span&gt;&lt;math&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; with the &lt;span&gt;&lt;math&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-axis) in electrically conducting low Prandtl number fluids under the paradigm of the Rayleigh–Bénard convection by performing three-dimensional direct numerical simulations. The control parameters, namely, the Chandrasekhar number (&lt;span&gt;&lt;math&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;) and the reduced Rayleigh number &lt;span&gt;&lt;math&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; (ratio of Rayleigh number to critical Rayleigh number), are varied in the ranges &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;1000&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mn&gt;20&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; for the Prandtl numbers &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Pr&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and 0.2 by considering three horizontal aspect ratios (&lt;span&gt;&lt;math&gt;&lt;mi&gt;Γ&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;): &lt;span&gt;&lt;math&gt;&lt;mfrac&gt;&lt;mrow&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/mfrac&gt;&lt;/math&gt;&lt;/span&gt;, 1 and 2. In the absence of the magnetic field, the convection starts in the form of steady rolls including the one parallel to the &lt;span&gt;&lt;math&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-axis. As the oblique horizontal magnetic field is switched on at an angle &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;ϕ&lt;/mi&gt;&lt;mo&gt;∈&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;,&lt;/mo&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;]&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; with the &lt;span&gt;&lt;math&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-axis, it is observed that the Lorentz force generated by the component of the magnetic field transverse to the axis of the convection rolls inhibits convection. Thus, with the application of the magnetic field, the convection is suppressed and restarts for a higher Rayleigh number in the form of steady convection rolls. The rolls can be oriented at angles 0° (steady parallel rolls, SPR) or 45° (steady oblique rolls, SOR&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) or 135° (steady oblique rolls, SOR&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) with the &lt;span&gt;&lt;math&gt;&lt;mi&gt;x&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;-axis depending on the choices of the parameters. A rich bifurcation structure consisting of standing and traveling flow patterns associated with these steady flow patterns for higher values &lt;span&gt;&lt;math&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; is investigated in detail. The oscillatory instability of the steady rolls is found to scale as &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;α&lt;/mi&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; with two distinct exponents, one each for weaker and stronger magnetic fields. The investigation reveals that for a given set of values of &lt;span&gt;&lt;math&gt;&lt;mi&gt;Q&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;mi&gt;Pr&lt;/mi&gt;&lt;/math&gt;&lt;/span&gt;, the heat transfer is inhibited with the increase of &lt;span&gt;&lt;ma","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105111"},"PeriodicalIF":2.8,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143873350","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":"Constitutive modeling of rock failure behavior under pressure conditions spanning the brittle–ductile transition","authors":"Sili Liu ,&nbsp;Lurong Hua ,&nbsp;Qizhi Zhu ,&nbsp;Jin Zhang ,&nbsp;Qiaojuan Yu ,&nbsp;Shuai Zhao ,&nbsp;Lunyang Zhao","doi":"10.1016/j.ijnonlinmec.2025.105117","DOIUrl":"10.1016/j.ijnonlinmec.2025.105117","url":null,"abstract":"<div><div>The brittle–ductile transition is a fundamental mechanical characteristic of rocks in a range of engineering applications. While various constitutive models have been proposed to predict rock failure, only a few are capable of quantitatively capturing the brittle–ductile transition. Moreover, to date, few existing models are able to uniformly describe the distinct mechanical behaviors of rocks in the brittle and ductile regimes. This paper presents a unified elastoplastic damage model capturing the mechanical behavior of rocks spanning the brittle–ductile transition. A subtly single cap-type plastic yield criterion is formulated in the effective stress space and a monotonic hardening function is introduced into the yield criterion to describe pre-peak hardening behavior accurately. The post-peak softening behavior is solely due to material damage, for which we propose a damage criterion. Unlike prevailing models, our hypothesis suggests that the damage process begins with localized cracking after reaching the peak stress, eliminating any accumulation of damage prior to the peak stress. In this context, the yield surface at peak stress state constitutes the real strength envelope. Furthermore, to accurately replicate post-peak softening behavior and brittle–ductile transition in rocks, we establish a theoretical correlation between residual damage and confining pressure. Numerical simulations are performed for three types of rock subjected to conventional triaxial compression. Comparisons between numerical predictions and test data demonstrate that the model effectively captures key features of mechanical behavior observed in these rocks. Particularly noteworthy is its ability to simulate the brittle–ductile transition.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105117"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850567","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":"Transverse and axial vibrations of masonry beams and towers","authors":"Maria Girardi","doi":"10.1016/j.ijnonlinmec.2025.105086","DOIUrl":"10.1016/j.ijnonlinmec.2025.105086","url":null,"abstract":"<div><div>Studying the effects of the earthquakes’ vertical component on the dynamic response of masonry buildings is still an open issue. This subject is investigated using a simplified masonry-like beam model with a generalized stress–strain relationship. The nonlinear dynamic equations that couple the transverse and axial oscillations of the beam are solved numerically. Some examples are presented and discussed, focusing on the structural typology of masonry towers and the recent earthquakes that threatened the North-Central Apennines in Italy.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105086"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868975","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":"Stability analysis of a spline-rotor system subjected to friction-induced self-excited vibrations","authors":"Peng Cao ,&nbsp;Runze Zhang ,&nbsp;Ye Wei ,&nbsp;Baian Hu ,&nbsp;Xinxing Ma ,&nbsp;Zhenguo Zhang","doi":"10.1016/j.ijnonlinmec.2025.105127","DOIUrl":"10.1016/j.ijnonlinmec.2025.105127","url":null,"abstract":"<div><div>Spline joints introduce cross-coupling, internal friction, and interface discontinuities, that can lead to system instability and self-excited vibrations under certain operating conditions. Predicting the onset conditions and amplitudes of self-excited vibrations in the spline-rotor system, as well as their dependence on physical parameters such as misalignment and interfacial friction, is crucial for effective design work. Therefore, in this study, a comprehensive stability analysis of a spline-rotor system subjected to self-excited vibrations induced by interfacial friction is carried out. First, the complex eigenvalue method is used to identify the equilibrium point stability. Then, numerical continuation methods are applied to perform a global stability assessment and to rapidly predict limit cycles. To improve computational efficiency, model reduction is integrated, which allows a systematic investigation of the effects of parameters on system stability and vibration response, elucidating the friction mechanism and influence laws. Through this in-depth study, the stability and nonlinear behavior of the spline rotor system subjected to self-excited vibration is revealed, providing crucial theoretical support for effective design strategies to mitigate system instability and self-excited vibration in rotating machinery.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105127"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852030","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":"Modeling photo-oxidation effects in semicrystalline polymer: Boundary-value simulations and experimental multiscale analysis","authors":"Ali Kassab ,&nbsp;Georges Ayoub ,&nbsp;Mustapha Makki ,&nbsp;Christopher Pannier ,&nbsp;Moussa Nait Abdelaziz","doi":"10.1016/j.ijnonlinmec.2025.105124","DOIUrl":"10.1016/j.ijnonlinmec.2025.105124","url":null,"abstract":"<div><div>This study presents a comprehensive computational framework designed to capture the mechanical property changes and damage accumulation in UV-aged semicrystalline polymers. The approach integrates time-dependent continuum damage mechanics with anisotropic plasticity and damage, implemented through user-defined subroutines in commercial finite element analysis (FEA) software. To account for UV-induced photo-oxidation, we introduce an experimentally informed photodegradation kinetics model, seamlessly coupled with the continuum damage mechanics formulation. Our focus is on semi-crystalline Low-Density Polyethylene (LDPE) films subjected to accelerated ultraviolet (UV) aging. Through extensive mechanical and rheological characterizations, we propose competing multi-scale mechanisms to describe the observed material behavior: initial strengthening, driven by chemi-crystallization, is followed by softening due to the formation of chemical cracks as UV exposure increases. The continuous decrease in strain to failure is attributed to oxidation-induced chain scission. The developed model is validated through FEA boundary-value problems modeling the experimentally tested samples. Comparative analysis between the simulated and experimental results highlights the model's accuracy in predicting mechanical behavior, damage progression, and fracture initiation. Overall, the proposed computational framework, along with its finite element implementation, delivers reliable and experimentally validated predictions.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105124"},"PeriodicalIF":2.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850499","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 stochastic evolution of spatial uncertainty along the process axis","authors":"N. Malkiel ,&nbsp;O. Rabinovitch","doi":"10.1016/j.ijnonlinmec.2025.105125","DOIUrl":"10.1016/j.ijnonlinmec.2025.105125","url":null,"abstract":"<div><div>This paper builds upon the existing concept of process axis analysis in strongly nonlinear structural problems by introducing a novel approach for assessing the evolution of spatial uncertainty. Specifically, it adapts the stochastic perturbation method to enable Random Field representation of uncertainty and analyze its effect along the process axis. As an example, the delamination process of a composite beam bonded to a substrate using an adhesive layer is looked at. The strongly nonlinear physical behavior and the uncertainty that accompanies such behavior are investigated along the axis of the nonlinear delamination process. This approach is innovatively developed to allow a random field representation of uncertainty by the adaptation of the stochastic perturbation method to the process axis analysis. Numerical results are compared with reference ones obtained by quadrature-rule numerical integration and Monte Carlo simulation. The ability to handle strongly nonlinear problems while avoiding the singularity and divergence of the stochastic analysis near snap-through and snap-back folds, achieved by means of the projection of the stochastic perturbation method to the process axis, and the representation of the parametric and spatial uncertainties of the structural properties by Random Fields are among the innovative and original contributions of the present work.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105125"},"PeriodicalIF":2.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852029","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":"FEM-SPH adaptive method for dynamic analysis of the diaphragm's fracture in hypersonic impulse facilities","authors":"Jiahao Zhang,&nbsp;Linjie Huang,&nbsp;Zixuan Wan,&nbsp;Xia Song,&nbsp;Gun Li,&nbsp;Jiang Lai","doi":"10.1016/j.ijnonlinmec.2025.105123","DOIUrl":"10.1016/j.ijnonlinmec.2025.105123","url":null,"abstract":"<div><div>The shock tunnel is a key land-based test facility used to study the aerodynamic performance of supersonic aircraft. The diaphragm is an essential component of the shock tunnel test, which acts as the trigger device. The critical rupture pressure of the diaphragm is significant because it determines the operating conditions for the shock tunnel test. However, when the diaphragm ruptures, it generates fragments that can pose risks to the safe operation of the test equipment. The finite element method (FEM) is the most commonly used approach for analyzing the dynamic response of diaphragm rupture. While FEM can accurately predict the critical rupture pressure and rupture time, it has limitations in simulating the fragments produced during the rupture process. This paper proposes a method for calculating the dynamic response of a shock tunnel diaphragm rupture by combining the finite element method and smoothed particle hydrodynamics (FEM-SPH) to address this limitation. This method has been verified for its accuracy in predicting critical rupture pressure and time. Additionally, the paper introduces a research method for characterizing the fragments using aggregated SPH particles. It analyzes the dynamic response characteristics of the diaphragm and the pieces during the rupture process.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105123"},"PeriodicalIF":2.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852027","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 pseudo-compressible dual 4-chain model of polymer networks for exploring rubber elasticity","authors":"Ziyu Xing","doi":"10.1016/j.ijnonlinmec.2025.105122","DOIUrl":"10.1016/j.ijnonlinmec.2025.105122","url":null,"abstract":"<div><div>Rubber elasticity has been a subject of studies for an extended period of polymer physics. Currently, the advancement of rubbery polymers is proceeding at an accelerated pace, and the network structure is exceptionally complex. To comprehensively comprehend the mechanical behavior exhibited by these rubbery materials, it is imperative to further evolve the theoretical framework of rubber elasticity. To understanding this problem, this study introduces a pseudo-compressible dual four-chain model for analyzing polymer networks and rubber elasticity. To address the lack of periodicity in the 4-chain model, a pseudo-compressible dual four-chain model is constructed, which accounts for intrinsic moments and volume effects. The model assumes isotropic of the polymer and affine motion of crosslinking points, which changed the coordinate system, leading to a simplified 4-chain model. Due to the poor symmetry of the 4-chain model, the force balance caused by chain deformation is different from that of traditional Langevin statistics models. Based on the phantom network model, preliminary estimates of volume effects were made using phenomenology and scaling equations. The proposed model is validated against experimental data from literature on various mechanical tests, including compressibility, uniaxial tension, uniaxial compression, pure shear, equi-biaxial tension, and biaxial strain tests. Using uniaxial tensile data from literature, the fitting results of different models (proposed dual 4-chain model, <em>p</em>-chain model, Yeoh model, Anssari-Benam model) are also used to illustrate the characteristics of the proposed model. The proposed constitutive model provides a new dual 4-chain strategy for exploring rubber elasticity.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"175 ","pages":"Article 105122"},"PeriodicalIF":2.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834016","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}