{"title":"Responses of any arbitrary initially stressed reference and the stress-free reference","authors":"Soumya Mukherjee","doi":"10.1016/j.ijnonlinmec.2025.105070","DOIUrl":"10.1016/j.ijnonlinmec.2025.105070","url":null,"abstract":"<div><div>The constitutive relation for an initially stressed reference is often determined by using the response of a virtual stress-free reference. However, identifying the constitutive relation of the original stress-free body can be challenging without conducting destructive tests. This paper presents three approaches for determining the response of a stress-free reference—or any arbitrary initially stressed reference—when the response of a particular initially stressed reference is known. Unlike standard practice, these approaches of changing reference configurations do not begin with a known stress-free state. The first and third approaches directly derive the constitutive relations of one stressed reference from another. The first approach is applicable to a specific constitutive relation of the known initially stressed state, while the third approach extends the first and is applicable to any constitutive form. The second approach uses any general response of a given stressed reference to identify the stress-free material. The response of the stress-free material is further analyzed and processed to determine the response of any stressed reference. We observe that even when the known initially stressed state is Green elastic, the arbitrarily stressed or stress-free references may exhibit implicit elasticity. Several explicit constitutive relations are also exemplified. One of the examples utilizes the invariants of Seth’s generalized strain measures. For experimental validation of this model, we transform the Treloar data to various initially stressed references. Model parameters corresponding to a specific stressed state are optimized by corroborating the model against the Treloar data associated with that reference. These optimized parameters are then used to determine the constitutive relations for the stress-free and other stressed reference configurations. The resulting constitutive relations for various references show identical alignment with the corresponding Treloar data, thereby validating the present approaches for changing the reference configuration. It is demonstrated that the developed models satisfy all restrictions related to the change of references. Furthermore, we develop universal relations for stress-free isotropic implicit elastic materials.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105070"},"PeriodicalIF":2.8,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610573","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}
Bijuan Yan , Guansen Qiao , Yihang Geng , Zhangda Zhao , Tao Yang
{"title":"An improved constitutive model for the rate-dependent mechanical behaviour of rubbery materials","authors":"Bijuan Yan , Guansen Qiao , Yihang Geng , Zhangda Zhao , Tao Yang","doi":"10.1016/j.ijnonlinmec.2025.105077","DOIUrl":"10.1016/j.ijnonlinmec.2025.105077","url":null,"abstract":"<div><div>In order to accurately predict the mechanical behaviour of fluororubber and silicone rubber under different strain rates, an improved model based on the existing strain rate-dependent viscoelastic constitutive models is proposed in this article. Firstly, a strain rate-dependent variable-order fractional model is established. Then, the method of combining theory and experiment is adopted to explore the influence of the key parameters on prediction accuracy. Following this, the relaxation time is found to be the key factor affecting the accuracy of the predicted results of the mechanical properties through the analyses. Finally, the model is improved by replacing the relaxation time with the viscoelastic coefficient. The results show that the relative errors of the stress prediction results are within 3% for silicone rubber and reduced by 1.7%–4.5% for fluororubber. These findings can provide theoretical references and support for the analysis of the mechanical properties of the similar types of viscoelastic materials.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105077"},"PeriodicalIF":2.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619526","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}
Gwladys Belone , Van Dong Do , Philippe Le Grognec , Philippe Rohart , Samir Assaf
{"title":"Analytical study of the elastoplastic buckling of conical shells under external pressure","authors":"Gwladys Belone , Van Dong Do , Philippe Le Grognec , Philippe Rohart , Samir Assaf","doi":"10.1016/j.ijnonlinmec.2025.105069","DOIUrl":"10.1016/j.ijnonlinmec.2025.105069","url":null,"abstract":"<div><div>Pressure vessels are traditionally made up of cylindrical shells and hemispherical or ellipsoidal ends, but in some cases, conical sections are also present so as to ensure the transition between cylindrical sections of different radii. The buckling phenomenon is one of the main failure mode of such pressure equipments, due to the thinness of the components and the compressive stresses commonly undergone throughout standard loads like external pressure, and thus an essential dimensioning factor. If the buckling behavior of cylindrical and spherical shells has been widely investigated in the literature, the specific case of conical shells has received much less attention, all the more so in plasticity. Therefore, the present paper aims to address the problem of elastoplastic buckling of a conical shell under external pressure in an analytical way. This study is based on the plastic bifurcation theory and relies on the simplest possible hypotheses in terms of kinematics, constitutive law and boundary conditions. However, in absence of closed-form expressions, approximate solutions for the critical pressure are sought, based on the choice of appropriate shape functions in the framework of the Rayleigh–Ritz method. Unlike the case of cylindrical or spherical shells under external pressure which display uniform pre-critical stress states, the stress field appears to be heterogeneous in the length direction of a conical shell, so that three scenarios may occur. A conical shell may buckle elastically, entirely in the plastic range, or in an intermediate situation where the shell is partially elastic and plastic at the critical time. The present analytical solution is validated against reference numerical results obtained through finite element computations, considering a wide range of geometric and material parameters so as to cover all three scenarios.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105069"},"PeriodicalIF":2.8,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643558","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":"Unveiling the dynamics of particle-reinforced electro-magneto-active circular membrane","authors":"Ankush Agrawal, Aman Khurana","doi":"10.1016/j.ijnonlinmec.2025.105064","DOIUrl":"10.1016/j.ijnonlinmec.2025.105064","url":null,"abstract":"<div><div>Electro-magneto-active (EMA) membranes are materials that integrate electromagnetic and active properties to form flexible, responsive surfaces. These membranes typically consist of a soft, elastic matrix embedded with magnetic or electromagnetic particles, which can be manipulated by external magnetic fields or electrical currents. This paper investigates the nonlinear dynamics of an electro-magneto-active circular membrane, a sophisticated smart actuator. Specifically, a continuum physics-based model is implemented to predict the membrane’s dynamic response to applied electro-magneto-mechanical loads. The obtained results offer valuable preliminary insights into the influence of both DC and AC dynamic actuation modes on the membrane’s nonlinear behavior. Notably, we find that increased particle reinforcement, as indicated by the filler content, significantly enhances polymer strength and reduces deformation. Also, an increase in shear modulus ratio results in a reduction in oscillation intensity and an enhancement in excitation frequency. Additionally, time–history response, Poincaré maps, and phase diagrams are utilized to evaluate the membrane’s stability, periodicity, beating phenomena, and resonant behavior. These findings are pivotal for advancing the design and functionality of smart membranes in various biomedical applications.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105064"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619565","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}
Chengyue Liu , Tao Hu , Hai Xie , Tengwu He , Miaolin Feng
{"title":"Numerical implementation for the cyclic elasto-plasticity model of Inconel 690 considering cyclic hardening followed by softening","authors":"Chengyue Liu , Tao Hu , Hai Xie , Tengwu He , Miaolin Feng","doi":"10.1016/j.ijnonlinmec.2025.105068","DOIUrl":"10.1016/j.ijnonlinmec.2025.105068","url":null,"abstract":"<div><div>This study investigates the cyclic elasto-plastic behavior of the nickel-based alloy 690 under fully reversed uniaxial strain load at room temperature. Through a series of experiments, it is found that the material undergoes initial cyclic hardening followed by prolonged softening. The strain range effect is also observed, as the rate of cyclic hardening/softening is influenced by strain amplitudes. To capture these behaviors, a nonlinear kinematic hardening rule combined with the strain memory surface is introduced, and the saturated value of backstress is considered as a function of both the accumulated plastic strain and the radius of the memory surface. Subsequently, the backward Euler method and the implicit integration algorithm are applied for numerical implementation. A user material subroutine UMAT is developed for the commercial software ABAQUS. Numerical simulations are conducted on the experiment specimens to validate the constitutive model. The results indicate that the model can describe the cyclic elasto-plastic behavior of the nickel-based alloy 690.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105068"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552722","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":"Experimental and numerical analysis of nonlinear velocity response for a cantilever","authors":"Nasser Firouzi , Fadi Dohnal , Tobias Gorbach , Tara Farizeh","doi":"10.1016/j.ijnonlinmec.2025.105067","DOIUrl":"10.1016/j.ijnonlinmec.2025.105067","url":null,"abstract":"<div><div>In this work, a comprehensive study on the large transient response of a clamped-free beam is done both experimentally and numerically. At the first stage, a custom setup is designed and the nonlinear velocity response of a cantilever is measured with high accuracy by a PSV QTec Scanning Vibrometer H Compact. In the next step, a nonlinear finite element analysis based on co-rotational formulation is derived by considering Euler-Bernoulli beam theory. Besides, to deal with time, the Newmark implicit method is utilized. The numerical evaluation of the derived formulation is validated with the experimental data. The results demonstrate that the obtained formulation can predict the nonlinear velocity response of the cantilever very well. The custom design and the numerical formulation in this work provide promising venue for design of advanced beam structures such as smart materials and adaptive systems.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"173 ","pages":"Article 105067"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534136","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}
Fulin Shen , Zilin Zhong , Xiaobin Xu , Jianhua Li , Qinxi Dong , Jian Deng
{"title":"In-plane simultaneous resonance instability behaviors of a fixed arch under a two-frequency radial uniformly distributed excitation","authors":"Fulin Shen , Zilin Zhong , Xiaobin Xu , Jianhua Li , Qinxi Dong , Jian Deng","doi":"10.1016/j.ijnonlinmec.2025.105056","DOIUrl":"10.1016/j.ijnonlinmec.2025.105056","url":null,"abstract":"<div><div>This paper delves into a theoretical and numerical exploration of the in-plane simultaneous resonance instability behaviors exhibited by a fixed arch subjected to a two-frequency radial uniformly distributed excitation. An intriguing and previously overlooked phenomenon of simultaneous resonance instability in fixed arches has been identified—specifically, the coexistence of superharmonic resonance and combination subharmonic resonance. The in-plane governing equation of motion was derived using Hamilton's principle and subsequently decoupled through the application of the Galerkin method. Employing the method of multiple scales, boundary excitation frequencies at varying amplitudes were determined, establishing dynamic instability zones and distinguishing between stable and unstable regions of the arch. These findings were further validated using both the finite element method and the fourth-order Runge-Kutta technique. The investigation brought to light a fascinating phenomenon wherein the concurrent manifestation of both 2-order superharmonic resonance and 1/2-order combination subharmonic resonance occurs when the sum of two excitation frequencies approaches twice the natural frequency of the arch, with one of them being approximately half of the natural frequency.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105056"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Neural controller for targeting a desired stationary distribution in stochastic systems","authors":"Wantao Jia , Zhe Jiao , Zhengrong Jin","doi":"10.1016/j.ijnonlinmec.2025.105058","DOIUrl":"10.1016/j.ijnonlinmec.2025.105058","url":null,"abstract":"<div><div>One of the major missions in the field of stochastic control is to design efficient control policies that guarantee the stochastic systems stabilize within some specified stationary distribution. In this paper, we propose a neural controller based on the stochastic asymptotic stability theory and the condition of detailed balance. A novel physics-informed learning procedure is introduced to update the parameters in a multi-output neural network which is utilized to approximate the controller. We also prove rigorously that the proposed controller is unique if it exists, which is essential in applications. Furthermore, several representative stochastic systems are used to illustrate the usefulness of this neural controller for the stabilization of these dynamical systems in distribution.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105058"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521259","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}
Yu Lin , Guilin Wen , Chengxiang Liu , Junfeng He , Jie Liu
{"title":"A magnetorheological elastomer-based hybrid vibration isolation system with semi-active control and quasi-zero stiffness performance","authors":"Yu Lin , Guilin Wen , Chengxiang Liu , Junfeng He , Jie Liu","doi":"10.1016/j.ijnonlinmec.2025.105063","DOIUrl":"10.1016/j.ijnonlinmec.2025.105063","url":null,"abstract":"<div><div>The quasi-zero stiffness (QZS) vibration isolation system suffers from conflicts between low-frequency and mid-to-high-frequency isolation, despite having outstanding low-frequency vibration isolation performance. Meanwhile, the semi-active control technology based on magnetorheological elastomers (MRE) can achieve good vibration isolation effects over a wide frequency range. However, its ability to isolate low-frequency vibrations is still restricted. To address the challenge, this paper proposes a hybrid vibration isolation system that combines QZS isolation technology with semi-active control technology based on MRE. The hybrid vibration isolation system consists of the QZS vibration isolation unit and the semi-active control unit. The inclined springs provide negative stiffness, while the MRE and linear vertical spring jointly provide positive stiffness. The magneto-mechanical properties of the MRE samples are analyzed, and a phenomenological constitutive model is established. The relationship between the magnetic field and control current in the hybrid system is determined through electromagnetic field simulation. The hybrid system's vibration isolation performance in passive mode as a QZS isolator with nonlinear damping properties is assessed using the harmonic method. The hybrid system's vibration isolation performance under random and harmonic excitations is then examined in semi-active control mode. The findings demonstrate that the hybrid system outperforms traditional QZS isolators in terms of vibration isolation performance in passive mode. Furthermore, it demonstrates excellent performance in the semi-active mode under both harmonic and random excitations, with good wideband low-frequency vibration isolation capabilities.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105063"},"PeriodicalIF":2.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143578508","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":"Multi-objective optimization of the asymmetric-grinding rail profile for sharply curved tracks on metro line","authors":"Fei Yang , Liang Gao","doi":"10.1016/j.ijnonlinmec.2025.105065","DOIUrl":"10.1016/j.ijnonlinmec.2025.105065","url":null,"abstract":"<div><div>Rail grinding is an effective strategy to improve the curve negotiation performance of metro vehicles. This paper develops a multi-objective optimization model for the design of the asymmetric-grinding rail profiles. The root-mean-square value of the derailment coefficient and the mean value of the rail wear of high rail are taken as two optimization objectives. A surrogate model, established using the results of the vehicle-track coupled dynamics simulations and non-uniform rail wear predictions, is used to calculate the optimization objectives. The multi-objective particle swarm optimization (MOPSO) model is applied to solve the multi-objective optimization model. The asymmetric-grinding rail profile of a sharp metro line is optimized by using the developed model, and the Pareto front of the multi-objective optimization problem is obtained. The performance of three typical asymmetric-grinding rail profiles in vehicle dynamics and rail wear rate is analyzed by comparing them with those of the original rail profile. The simulation results show that the optimized asymmetric grinding of rail profiles achieves the optimization objectives of reducing both the derailment coefficient and the mean value of rail wear on high rail. Due to the conflicting relationship between the two objective functions, an optimized asymmetric-grinding of rail profiles in the Pareto front that could balance both the wheel-rail safety and rail wear is chosen as the best rail grinding strategy.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"174 ","pages":"Article 105065"},"PeriodicalIF":2.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521258","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}