{"title":"An accurate and locking-free geometric exact beam formulation on the special orthogonal group SO(3)","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104925","DOIUrl":"10.1016/j.ijnonlinmec.2024.104925","url":null,"abstract":"<div><div>An accurate and locking-free geometric exact beam formulation (GEBF) on the special orthogonal group SO(3) is developed for slender beams with large deformations and large rotations. Due to the nonlinear nature of the spatial rotations, the classical GEBFs usually have a non-constant mass matrix and complex expressions of inertia forces; meanwhile, the singularity and locking issues are also key matters of concern. Aiming at resolving these drawbacks, two main contributions are achieved in the present work. First, the angular velocity is independently interpolated, resulting in a constant mass matrix and explicitly representable inertial forces, which can offer significant advantages for efficient dynamic simulations. Second, inspired by the assumed natural strain method in shell theory, the stretch-shear strain is interpolated to obtain simplified and locking-free elastic forces, which is a new attempt to alleviate the locking problems for the GEBFs. In addition, the special orthogonal group SO(3) is utilized for updating incremental rotation vectors to eliminate singularities, and objective strain measurement is achieved by employing relative rotation vector interpolation. The effectiveness and superiority of the developed low-order and high-order elements are demonstrated through numerical simulations of standard benchmark examples. The present work contributes to the advancement of accurate and reliable formulation for slender beams; the constant mass matrix, the locking-free characteristics, and the elegant form of the formulation make it particularly suitable for multibody dynamic analysis.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431932","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":"Optimization method of vibration isolation performance of the 6DOF vibration isolation platform based on different configurations","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104924","DOIUrl":"10.1016/j.ijnonlinmec.2024.104924","url":null,"abstract":"<div><div>The configuration optimization methods are developed to design the six degree of freedom (6DOF) passive vibration isolation platform with superior isolation performance. According to different position arrangements, various configuration vibration isolation platforms, including the 33 type, 63 type, 66–1 type, and 66–2 type, are designed and systematically analyzed. Through analysis of the geometric characteristics of the configuration platforms, the nonlinear dynamical equations for each configuration vibration isolation platform are established using Hamilton's principle. Utilizing the transmission rate as an evaluation index, the isolation performance of each platform in six directions (three translational and three rotational) is systematically studied. The results indicate that: (a) Through the comparative analysis of different configuration vibration isolation platforms, it can be found that the 66–1 configuration not only has the largest loading capacity but also owns the best isolation performance in the <em>x</em>, <em>y</em>, and <em>γ</em> directions. The 33 configuration has better isolation performance in the <em>z</em>, <em>α</em>, and <em>β</em> directions, while having greater loading capacity; (b) Through configuration optimization, a 6DOF vibration isolation platform can be obtained with high static stiffness in the vertical direction and low dynamic stiffness in other external excitation directions. This kind of HSLDS characteristics will significantly enhance the isolation performance of the vibration isolation platform; (c) Workspace analysis under different configurations reveals that the 66–1 configuration offers the largest workspace in all six directions, followed by the 63 configuration, while the workspaces of the 33 and 66–2 configurations are similar.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431933","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":"Boundary excitation of nonlinearly modulated bending strain waves in a metamaterial","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104922","DOIUrl":"10.1016/j.ijnonlinmec.2024.104922","url":null,"abstract":"<div><div>A non-linear modulation of bending waves in a metamaterial mass-in-mass lattice model is studied. Various kinds of non-linear wave modulation are obtained using a harmonic boundary excitation. It is shown, that these waves can be described by an asymptotic simplification of the equations of motion resulting in a non-linear modulation equation for the displacements. Exact periodic traveling wave solutions to the equation demonstrate a dependence on the sign of the equation coefficients or the elastic parameters of the original model. Dispersion relation for the carrier part of the solution is obtained as a function of wave number versus frequency, it is found how its solutions relate to the acoustic and optic branches and the band gap. This form of the dispersion relation is further used for a description of numerical results on the wave modulation by a harmonic boundary excitation.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431935","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":"Analytical solution of couple-mass-spring systems by novel homotopy perturbation method","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104923","DOIUrl":"10.1016/j.ijnonlinmec.2024.104923","url":null,"abstract":"<div><div>In this paper, a novel homotopy perturbation method is employed to estimate the approximate angular frequencies of highly nonlinear oscillators. This innovative methodology is extended to generate periodic solutions for the nonlinear free vibration observed in a conservative couple-mass-spring system. The system is characterized by both linear and nonlinear stiffness, specifically incorporating cubic nonlinearity. The application of this technique involves a detailed analysis of two practical instances of such systems. The validation process, comparing the results against published findings and exact solutions, reveals a notable alignment in the approximated angular frequencies and the corresponding periodic solutions. Noteworthy for its precision and easy to use application, this approach proves suitable for addressing a diverse range of nonlinear oscillatory problems encountered in both scientific and engineering domains.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142431934","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":"Buckling disappearance via merging/divergence in a nonlinear three-d.o.f. system with linear constitutive law","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104920","DOIUrl":"10.1016/j.ijnonlinmec.2024.104920","url":null,"abstract":"<div><div>The phenomenon of buckling disappearance, occurring in a parameter-dependent family of systems admitting a nontrivial fundamental path, is studied. Two different forms of disappearance are detected, namely: (i) the <em>divergence</em>, in which the critical load continuously tends to infinity, and (ii) the <em>merging</em>, in which two critical loads approach each other, coalesce, and then disappear at a finite value of the critical load. It is shown that the two phenomena can be exhibited by the same mechanical system, when a suitable elasto-geometric parameter is varied. More importantly, it is proved that merging continuously changes into divergence when a second parameter is changed. A paradigmatic system is chosen to illustrate the two forms of buckling, <em>i.e.</em>, a three degree-of-freedom spherical pendulum, elastically constrained at the ground, loaded by a transverse force and/or a conservative couple, made of two longitudinal potential forces. The springs are taken elastically linear, to stress the fact that divergence not necessarily calls for introducing a nonlinear constitutive law, as also mentioned in literature. Only a linear bifurcation analysis is carried out here, aimed to find the bifurcation points along the nonlinear fundamental path. However, due to the presence of non-negligible prestrains, such a bifurcation problem is governed by nonlinear algebraic equations, whose number of roots cannot be predicted in advance.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420071","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":"A novel cut-out piezoelectric beam with limiters for broadband energy harvesting","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104919","DOIUrl":"10.1016/j.ijnonlinmec.2024.104919","url":null,"abstract":"<div><div>In this paper, we proposed a novel cut-out piezoelectric beam with two pairs of motion limiter for broadband operation. By means of the finite element simulation, a superior geometric structure of the corresponding linear model is designed and the model parameters are determined, then the simulation results are verified by experiments. The subsequent experiments mainly investigate the effect of the position of the limiter on the beam and the size of the limiting gap on the amplitude–frequency response of the system. The experimental results show that the frequency bandwidth of the first resonance peak can be significantly expanded from 2.45Hz to 6.28Hz by selecting suitable limiter parameters, which can increase of 256.33% compared with no limiter. Meanwhile, limiters also cause a maximum 171.79% increase in the primary resonance voltage amplitude, and the level of anti-resonance valley can be increased up to 5.35 times. Finally, the influence of external resistance load on the output power of the system is discussed through detailed parametric study, and the maximum power output of 370<span><math><mi>μ</mi></math></span>W is achieved.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420072","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":"On robust control of transmission squawk in a medium-duty vehicle","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104915","DOIUrl":"10.1016/j.ijnonlinmec.2024.104915","url":null,"abstract":"<div><div>Torsional oscillations can pose a significant challenge in automatic transmissions, including those stemming from instabilities induced by friction in the clutch system during shifts. Examples include chatter, squeal, shudder, judder and squawk. Transmission squawk is more than just an annoying noise; it is a symptom of underlying issues that, if left unaddressed, can lead to significant structural failures. Squawk is a high-frequency torsional oscillation, predominantly induced due to a negative friction slope and the presence of a weakly damped oscillating mode in the transmission system. Although numerous passive methods are available to prevent the squawking of the clutch in automotive transmission, the significant drawback of passive methods is the limited duration of effectiveness. This paper particularly focuses on the mitigation of squawk using active control techniques. Since squawk occurs in clutch output, therefore, the output speed is used as the measured signal and clutch clamping force as the control action. The primary objective is to develop a control strategy that effectively dampens squawk oscillations while also minimizing control effort, a crucial aspect that has been overlooked in previous research on robust control of friction-induced vibrations (FIV) in context of automatic transmissions. The effectiveness of the designed controller is tested on an experimentally validated non-linear vehicle-level simulation model of a 9-speed automatic transmission. With the designed controller, the squawk oscillations are successfully suppressed. Comparisons with industrial routine PI controller are made to demonstrate the performance of <span><math><mi>μ</mi></math></span>-optimal controller in terms of minimal control effort and smoother clutch engagement.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420074","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":"PDE-based anti-disturbance attitude and vibration control of flexible satellite under output constraints","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104914","DOIUrl":"10.1016/j.ijnonlinmec.2024.104914","url":null,"abstract":"<div><div>In this paper, an anti-disturbance control strategy is exploited for the attitude reorientation and vibration damping of flexible satellite under disturbances and output constraints. The flexible satellite is formulated by partial differential equations (PDEs) and the exploited controller extends the existing results from the following two aspects. (1) The exploited controller is capable of handling the time-varying output constraints by incorporating the barrier Lyapunov function (BLF) with a coupling-based item through Lyapunov analysis. (2) The exploited controller possesses the excellent disturbance rejection property by introducing two disturbance observers to separately identify the disturbance torque and force. The asymptotic stability of the closed-loop system is strictly evaluated. The exploited controller can restrain the attitude reorientation error and the tip deformation always in the predefined output constraints. Lastly, comparative simulations validate and highlight the main results.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420073","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":"Differential growth and shape formation of a flower-shaped structure","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104918","DOIUrl":"10.1016/j.ijnonlinmec.2024.104918","url":null,"abstract":"<div><div>Morphogenesis, which is a complex interplay of biological, chemical, and physical processes, facilitates differential growth in various biological systems, particularly in plant organs, such as petals and leaves. Although recent studies have increasingly delved into the mechanical aspects of these biological structures, there remains a lack of a comprehensive quantitative understanding of shape formation induced by differential growth in plant organs. Thus, this study addressed this gap by employing a multifaceted approach encompassing theoretical analyses and comprehensive finite element analysis of the effect of differential growth on the shape of a cylinder into a flower shape. Based on the derivation of the strain energy expressions for the axisymmetric and asymmetric configurations, the shape function of the growing flower-like structures were calculated through mathematical optimization. The findings of this study shed light on the influence of the growth function, geometric characteristics, and material properties. As the wave number increased, the final configuration tended to have smaller waves, whereas a longer cylinder buckled more easily and the thickness had a minimal effect. This study offers insights that can pave the way for innovative geometrical designs, thereby providing inspiration for applications on both micro-and macroscales, such as in the realms of self-assembly of soft robotics and flexible electronics.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419991","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":"Frequency dependence of nonlinear elastic moduli of polystyrene","authors":"","doi":"10.1016/j.ijnonlinmec.2024.104913","DOIUrl":"10.1016/j.ijnonlinmec.2024.104913","url":null,"abstract":"<div><div>In this paper we present experimental investigation of the frequency dependence of nonlinear elastic (Murnaghan) moduli of polystyrene samples by the ultrasonic method based on the acousto-elastic effect. Measurements were performed in a wide frequency range, from 250 kHz to 2.5 MHz. The absolute values of the Murnaghan moduli demonstrated considerably nonlinear dependencies on the ultrasound frequency. While at higher frequencies above <span><math><mo>∼</mo></math></span>600 kHz no significant variations of the moduli occurred, at lower frequencies a drastic rise of absolute values in several orders of magnitude has been observed. The values obtained at lower frequencies were utilized for theoretical estimation of parameters of a strain solitary wave in this material. The data obtained correlated well with the parameters obtained experimentally and allowed for explaining the long-lasting discrepancy between theoretical estimations and experimental results.</div></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420070","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}