International Journal of Non-Linear Mechanics最新文献

{"title":"Experimental and numerical investigations of the effects of bundled conductor on seismic responses of interconnected electrical equipment","authors":"Chang He ,&nbsp;Yanyan Guo ,&nbsp;Chengwei Zhou ,&nbsp;Wang Zhu ,&nbsp;Lizhong Jiang","doi":"10.1016/j.ijnonlinmec.2024.104956","DOIUrl":"10.1016/j.ijnonlinmec.2024.104956","url":null,"abstract":"<div><div>With a main function of power transmission, bundled conductors bring in strong nonlinearity for the connected electrical equipment in substations. Investigations of their effects on seismic responses of interconnected electrical equipment (IEEQ) are few in literature, lacking studies from an experimental perspective. Thus, shaking table tests were performed on a scaled ultra-high voltage IEEQ. The tests examine the effects of slackness, bending stiffness, number of spacers, and damping of the bundled conductors. Besides, the influence of earthquake input directions is also analysed. Moreover, a numerical model is developed to conduct parameter analyses to investigate the influence of bundled spacing and equipment frequency. The results indicate that the connection of the conductors reduces the IEEQ relative displacement. It overall increases the stress responses of the higher-frequency equipment while reduces those of the low-frequency equipment. The effects of slackness are related to the damping and stiffness effects of bundled conductors, since the latter can decrease the seismic responses of the IEEQ. Besides, the effects of bundled conductors on the out-of-plane and vertical responses of the IEEQ can be neglected per the test results. Finally, bundled conductors may twist during earthquakes, the spacers thereby should be positioned appropriately to prevent this issue.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"169 ","pages":"Article 104956"},"PeriodicalIF":2.8,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699464","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 generalized incremental harmonic balance method by combining a data-driven framework for initial value selection of strongly nonlinear dynamic systems","authors":"Y.L. Li ,&nbsp;J.L. Huang ,&nbsp;W.D. Zhu","doi":"10.1016/j.ijnonlinmec.2024.104951","DOIUrl":"10.1016/j.ijnonlinmec.2024.104951","url":null,"abstract":"<div><div>The incremental harmonic balance (IHB) method is a semi-analytical and semi-numerical method that consists of the harmonic balance process and the Newton–Raphson iteration process, which can accurately obtain solutions of strongly nonlinear dynamic systems, and has been successfully applied to many practical problems. However, it is difficult to choose proper initial values for the Newton–Raphson iteration process, especially for strongly nonlinear dynamic systems, which can cause divergence of the IHB method. A novel generalized IHB method by combining a data-driven framework to obtain feasible initial values for strongly nonlinear dynamic systems is proposed in this work. In the proposed data-driven framework, an artificial neural network (ANN) is trained to learn the mapping between small system parameters of a weakly nonlinear dynamic system and corresponding solutions of the IHB method. The amount of data required for training is determined by the number of system parameters, which is usually only a few hundreds to a few thousands, making the training process very expeditious. Once the trained ANN receives other system parameters of a nonlinear dynamic system, it can immediately output a set of feasible initial values for the IHB method, which can make the IHB method quickly converge. Results from extensive testing indicate that the mapping learned by the ANN is effective not only for weakly nonlinear dynamic systems that are characterized by smaller system parameters, but also for strongly nonlinear dynamic systems in most cases that involve larger system parameters. During the testing for strongly nonlinear dynamic systems, successful convergences generate new training data. These data can be leveraged to further fine-tune the ANN to yield an improved ANN, which allows continuous refinement of the ANN and enhances prediction of initial values for strongly nonlinear dynamic systems. With the introduction of this simple yet highly efficient data-driven initial value selection framework, the applicability of the IHB method can be significantly enhanced. Three numerical examples are presented to show the efficiency and advantages of the present methodology.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"169 ","pages":"Article 104951"},"PeriodicalIF":2.8,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699376","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":"Numerical simulation of stress and permeability evolution in damaged coal","authors":"Xianghe Gao ,&nbsp;Feng Gao ,&nbsp;Ning Zhang ,&nbsp;Hongmei Cheng ,&nbsp;Yan Xing","doi":"10.1016/j.ijnonlinmec.2024.104953","DOIUrl":"10.1016/j.ijnonlinmec.2024.104953","url":null,"abstract":"<div><div>Mining disturbance is the underlying cause of dynamic disasters such as coal-rock deformation, gas outbursts, and roof water inrush. Mining disturbance leads to damage in coal-rock structures and closely relates to stope cracks' distribution characteristics. Therefore, it is crucial to investigate the coupling effects of the stress field, damage field, and seepage field of coal. Firstly, we established a mechanical model considering the coupling effect of damage and elastoplasticity, which aimed to describe the softening process of coal-rock mechanical parameters and the mutation law of the permeability coefficient in the damage process. Next, we developed a pore-fracture fractal model of damaged coal. It was used to elucidate the inherent relationship between damage and pore-fracture characteristics in the process of coal-rock crushing. We then proposed a quantitative evaluation method for determining the permeability characteristics of coal under the influence of mining disturbances. Finally, a numerical simulation of damaged coal ‘s mechanical behavior and seepage characteristics under stress-seepage coupling was conducted. The development model's effectiveness was verified through comparison with experimental results. In summary, our research offered a solid scientific foundation for quantitative evaluation and accurate prediction of the evolution law of coal-rock permeability characteristics under the influence of mining disturbance.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104953"},"PeriodicalIF":2.8,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655232","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":"Stick–slip oscillations in the low feed linear motion of a grinding machine due to dry friction and backlash","authors":"Zsolt Iklodi ,&nbsp;Petri T. Piiroinen ,&nbsp;Oier Franco ,&nbsp;Xavier Beudaert ,&nbsp;Zoltan Dombovari","doi":"10.1016/j.ijnonlinmec.2024.104940","DOIUrl":"10.1016/j.ijnonlinmec.2024.104940","url":null,"abstract":"<div><div>This paper deals with mechanical modelling and numerical bifurcation analysis of stick–slip oscillations that plague extremely low feed grinding operations. Based on experimental observations, a novel two degree of freedom mechanical model of a grinding machine feed drive system is formulated, which incorporates Stribeck-type dry friction, position and velocity controller dynamics, and actuator backlash. Loss and re-establishment of contact between the feed drive elements is modelled through both rigid-body impacts and a contact-stiffness model. The resulting piecewise-smooth equations of motion are subjected to detailed stability and bifurcation analysis with the help of shooting and collocation based numerical continuation tools. Major focus is attributed to the influence of the feed velocity and the control-loop parameters as well as the identification of stable, stick–slip free parameter regimes. Finally, a controller enhancement strategy is proposed, based on event-driven integrator reset rules, to help limit the amplitude of arising limit-cycle oscillations.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104940"},"PeriodicalIF":2.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655298","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":"Efficient structural optimization under transient impact loads using multilayer perceptron and genetic algorithms","authors":"Haojie Ma ,&nbsp;Xiao Kang ,&nbsp;Shengyu Duan ,&nbsp;Ying Li","doi":"10.1016/j.ijnonlinmec.2024.104950","DOIUrl":"10.1016/j.ijnonlinmec.2024.104950","url":null,"abstract":"<div><div>Currently, there is a lack of structural optimization methods when a structure is suffering transient impact load, considering nonlinear factors such as material plasticity and strain rate effect. The utilization of derivative-free algorithms also increases computational expenses. Accordingly, this paper presents a novel structure transient optimization approach based on multilayer perceptron combined with a derivative-free optimization method, which can efficiently solve the transient structure dynamics optimization problem with multiple optimization objects. In this approach, the area to be optimized is cut by several closed B-spline curves whose shapes are controlled by several parameters and can be varied and merged at each optimization iteration step. The structure's transient analysis process is replaced by a machine learning based surrogate model, which is trained by thousands of results from the FEM explicit transient simulation. Additionally, nearly orthogonal Latin hypercube sampling is utilized to simplify parameter dimensionality, reduce the training data set, save calculation time, and give the training data set a more comprehensive range of design parameters. In our optimization process, our design target is to minimize the peak reaction force while with the constrain of ensuring enough stiffness and mass. The results demonstrate our proposed methods could efficiently handle transient optimization problems without sensitivity calculations, exhibiting strong generalization capabilities.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104950"},"PeriodicalIF":2.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655296","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":"Bursting oscillations with multiple crossing bifurcations in a piecewise-smooth system","authors":"Ying Wang ,&nbsp;Zhixiang Wang ,&nbsp;Chun Zhang ,&nbsp;Qinsheng Bi","doi":"10.1016/j.ijnonlinmec.2024.104938","DOIUrl":"10.1016/j.ijnonlinmec.2024.104938","url":null,"abstract":"<div><div>This paper aims to investigate the non-smooth bifurcations and to uncover the underlying dynamics that lead to bursting patterns within a two-scale piecewise-smooth system. The system is established by applying a modification scheme to a fourth-order Chua’s circuit, with a periodic external excitation current acting as the slow state variable. Several smooth as well as non-smooth bifurcations are discovered within the fast subsystem by utilizing theoretical and numerical methods. Two special non-smooth bifurcations have been discussed. The first is the multiple crossing bifurcation involving the boundary equilibrium, which exhibits the behavior of both the turning point and Hopf bifurcation. The second arises from an encounter between a saddle-focus and the trajectory of a non-smooth chaotic solution, which can result in the vanishing or appearance of a non-smooth chaotic attractor. Four typical bursting patterns associated with these two non-smooth bifurcations in the established slow–fast system are observed, and the mechanisms behind them are revealed based on bifurcation analysis.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104938"},"PeriodicalIF":2.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655295","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 geometric variations on the wing rock of blended wing–body aircraft","authors":"Waseeq Siddiqui ,&nbsp;Adnan Maqsood ,&nbsp;Shuaib Salamat ,&nbsp;Hongyi Xu ,&nbsp;Dan Xie","doi":"10.1016/j.ijnonlinmec.2024.104934","DOIUrl":"10.1016/j.ijnonlinmec.2024.104934","url":null,"abstract":"<div><div>Blended wing–body configurations are anticipated to dominate future transport and military aerospace designs. The departure of the conventional tube-wing configuration has opened several areas of investigation. These designs are susceptible to lateral instability during landing, takeoff, and maneuvering flight despite having improved aerodynamics because of their tailless nature. One of these instabilities, Wing-Rock, poses significant performance and operational difficulties and can potentially cause crashes. Though experimental and numerical studies of the aerodynamics and stability of blended wing–body configurations have been conducted, wing-rock characteristics still need to be identified in the literature. This research aims to investigate these characteristics at low subsonic speeds with varying outboard sweep and geometric twist angles. The study includes a numerical approach based on the rigid body free-vibration method in single roll degree of motion, which uses three-dimensional unsteady Reynolds’ Average Navier Stokes equations, and an analytical approach based on the multiple time scale method, which captures the crucial aspect of the wing rock system. The findings show that the geometrical parameters significantly impact the wing rock characteristics, which are unique to such novel tailless designs.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104934"},"PeriodicalIF":2.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655299","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":"Data-driven bifurcation analysis using parameter-dependent trajectories","authors":"Jesús García Pérez ,&nbsp;Leonardo Sanches ,&nbsp;Amin Ghadami ,&nbsp;Guilhem Michon ,&nbsp;Bogdan Epureanu","doi":"10.1016/j.ijnonlinmec.2024.104937","DOIUrl":"10.1016/j.ijnonlinmec.2024.104937","url":null,"abstract":"<div><div>Identification of bifurcation diagrams in nonlinear systems is of great importance for resilient design and stability analysis of dynamical systems. Data-driven identification of bifurcation diagrams has a significant advantage for large dimensional systems where analysis of the equations is not possible, and for experimental systems where accurate system equations are not available. In this work, a novel forecasting approach to predict bifurcation diagrams in nonlinear systems is presented using system trajectories before instabilities occur. Unlike previous techniques, the proposed method considers a varying bifurcation parameter during the system response to perturbations. Combined with an asymptotic analysis provided by the method of multiple scales eliminates the requirement of using multiple measurements and allows the novel technique to predict the bifurcation diagram using a single system recovery. The proposed approach allows stability analyses of nonlinear systems with limited access to experimental or surrogate data. The novel technique is demonstrated through its application to a Hopf bifurcation, highlighting its inherent advantages. Subsequently, the method is employed in the analysis of an aeroelastic system that shows both supercritical and subcritical Hopf bifurcations. The findings reveal great accuracy, achieved with a reduced number of measurements, while enhancing versatility.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104937"},"PeriodicalIF":2.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593171","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 vibration analysis of composite and functionally graded material shell structures: A literature review from 2013 to 2023","authors":"Vignesh Palani,&nbsp;Ashirbad Swain","doi":"10.1016/j.ijnonlinmec.2024.104939","DOIUrl":"10.1016/j.ijnonlinmec.2024.104939","url":null,"abstract":"<div><div>Owing to the improved mechanical properties of composites and functionally graded materials (FGMs), their applications have been realised in various engineering domains, such as aerospace, marine, automobile, and defence. Materials’ property plays a crucial role in dictating the dynamics of shell structure. Although much research has been conducted in structural dynamics, researchers are still working to develop new theories for structure and materials for composite shell structures to investigate their dynamic behaviour with various computational approaches involving different shell theories and experimental techniques. Apart from the linear analysis, researchers have also focused on the nonlinear dynamic behaviour of the shell structure with various shell theories. But still, this field of research remains vibrant for many researchers. This review encapsulates some critical articles in the field of the dynamics of both composite and FGM shell structures involving nanocomposite, viscoelastic and hyperelastic material systems. The motive of the study is also to highlight the analyses of the shear deformation theories employed for the development of formulations of shell structures, including geometrical and material nonlinearity, for the analysis of the dynamics involved in closed shells, panels, and such structures under fluid-structure interaction.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104939"},"PeriodicalIF":2.8,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592693","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":"Flow of fluids with pressure-dependent viscosity down an incline: Long-wave linear stability analysis","authors":"Benedetta Calusi","doi":"10.1016/j.ijnonlinmec.2024.104930","DOIUrl":"10.1016/j.ijnonlinmec.2024.104930","url":null,"abstract":"<div><div>In this paper, we investigate the linear stability of a gravity-driven fluid with pressure-dependent viscosity flowing down an inclined plane. The linear stability analysis is formulated using the long-wave approximation method. We show that the onset of instability occurs at a critical Reynolds number that depends on the material and geometrical parameters. Our results suggest that the dependence of the viscosity on pressure can influence the stability characteristics of the flow down an incline.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"168 ","pages":"Article 104930"},"PeriodicalIF":2.8,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655297","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}