Showing papers on "Vibration published in 2021"
TL;DR: The statistical analysis, stochastic analysis and frequency analysis are performed to make sense of the effect of the random track irregularities on the pantograph-catenary interaction, and the reliability of the pantographs shows a continuous decrease in the degradation of rail quality.
120 citations
TL;DR: In this paper, the authors investigated a technique for broadband vibration suppression using a graded metamaterial beam, where a series of local resonators with the same mass but different natural frequencies are attached to the beam, and a design strategy was proposed, and used to tune the frequency spacing to get a wide attenuation region.
118 citations
TL;DR: A modified stacked auto-encoder that uses adaptive Morlet wavelet is proposed to automatically diagnose various fault types and severities of rotating machinery and experimental results show that the proposed method is superior to other state-of-the-art methods.
Abstract: Intelligent fault diagnosis techniques play an important role in improving the abilities of automated monitoring, inference, and decision-making for the repair and maintenance of machinery and processes In this paper, a modified stacked auto-encoder (MSAE) that uses adaptive Morlet wavelet is proposed to automatically diagnose various fault types and severities of rotating machinery Firstly, the Morlet wavelet activation function is utilized to construct an MSAE to establish an accurate nonlinear mapping between the raw nonstationary vibration data and different fault states Then, the nonnegative constraint is applied to enhance the cost function to improve sparsity performance and reconstruction quality Finally, the fruit fly optimization algorithm (FOA) is used to determine the adjustable parameters of the Morlet wavelet to flexibly match the characteristics of the analyzed data The proposed method is used to analyze the raw vibration data collected from a sun gear unit and a roller bearing unit Experimental results show that the proposed method is superior to other state-of-the-art methods
86 citations
TL;DR: In this article, a lever-type vibration isolator with eddy current damping (LVI-ECD) is proposed, which can broaden the isolation band by adjusting the lever ratio and improve the vibration suppression performance with EDD.
80 citations
TL;DR: In this article, the nonlinear amplitude-dependent material property of fiber-reinforce composites (FRCs) and partial bolt loosening boundary conditions are taken into account, where the Rayleigh-Ritz method is employed to derive the equations of motion for FRCCSs from which the natural frequencies, damping ratios, and forced response can be obtained.
78 citations
TL;DR: The nonlinear passive isolation is effective for wide frequency bandwidth than the linear isolation system and the nonlinear energy harvesting system shows a great scope to harvest energy from wide ranges of excitations.
Abstract: Vibration present on various levels in many engineering fields and hence vibration mitigation has become a subject of intense study. The nonlinear vibration isolation devices are effective for broad frequency bandwidth and can provide better vibration isolation than linear devices. The need for nonlinearity in stiffness and damping characteristics has motivated researchers to apply the nonlinearity found in mechanisms or materials in the passive vibration control devices. This review discusses the applications of nonlinearity in the passive vibration control devices to provide an understanding of how the nonlinearity is applied and useful in the implemented system. Further, applications for nonlinearity can also be extended in the energy harvesting devices, Nonlinear energy sink, metamaterials for the purpose of vibration isolation and energy harvesting. The need for nonlinearity also encouraged research work through inspiration from the nature called bio-inspired devices. The bio-inspired devices mimic the nonlinearity of the biological system to suppress the vibrations. The nonlinear passive isolation is effective for wide frequency bandwidth than the linear isolation system. Further, the nonlinear systems also reduce transmissibility much efficiently than the linear system. The nonlinear energy harvesting system shows a great scope to harvest energy from wide ranges of excitations. The bio-inspired devices also are proven to be effective in vibration isolation. Additionally the design of the metamaterial with nonlinearity in the microstructure, proves to be promising in the vibration suppression applications. Based on the review, the nonlinearity introduced into the systems has greater benefits than the linear systems.
78 citations
TL;DR: The present work provides a comprehensive review on the recent advances in nonlinear vibration energy harvesting and vibration suppression technologies and in particular, the latest developments in multifunctional hybrid technologies are proposed.
Abstract: Limited by the structure, the high-efficiency vibration energy harvesting and vibration suppression have always been a theoretical bottleneck and technical challenge in this field. The nonlinear design of the new vibration structure is an indispensable link in the development of vibration energy harvesting and vibration suppression technologies. Nonlinear technologies not only have the potential to improve the efficiency of the energy harvesters by increasing the useful frequency bandwidth and output power but also have the potential to improve the efficiency of vibration suppressors by reducing the transmission rate and transfer energy. Nonlinear vibration energy harvesting and vibration suppression technologies have been salient topics in the literature and have attracted widespread attention from researchers. The present work provides a comprehensive review on the recent advances in nonlinear vibration energy harvesting and vibration suppression technologies. In particular, the latest developments in multifunctional hybrid technologies are proposed. Various key aspects to improve the performance of nonlinear vibration energy harvesting and vibration suppression systems are discussed, including implementations and configuration designs, nonlinear dynamics mechanisms, various optimizations, multifunctional hybrid, application prospects, and future outlooks.
77 citations
TL;DR: In this paper, an electromagnetic Stewart platform with high static and low dynamic stiffness is explored to reduce the vibration in six degrees of freedom (6-dofs) and simultaneously harvest energy.
76 citations
TL;DR: In this paper, an ultrasonic vibration plate device enabling the longitudinal full-wave and transverse half-wave (L2T1) vibration mode for UVAG was proposed, and the characteristics of coupled vibration in different directions were analyzed on the basis of apparent elastic method and finite element method.
75 citations
TL;DR: In this article, the double-leaf acoustic black hole beam embedded mass oscillator is used for vibration isolation, and different elastic wave modulation effects are discussed, such as strong wave trapping region corresponds to the anti-symmetrical vibration attenuation (Fano-like resonance) and the weak wave trapping regions correspond to the symmetrical vibration scattering (Bragg scattering).
71 citations
TL;DR: In this article, an analytical model for fiber reinforced polymer composite cylindrical shells (FRPCCSs) accounting for material and geometric nonlinearities and thermal effect is proposed, which is capable of predicting natural frequencies, damping ratios, and resonant responses under different excitation amplitudes and temperatures.
TL;DR: In this paper, the anti-vibration characteristics of a dish solar concentrator (DSC) system with wind-induced vibration, based on fluid-solid interaction method, are investigated and the useful results are concluded and obtained.
TL;DR: In this article, the authors proposed the theory and method of vibration isolation and energy harvesting based on the high-order quasi-zero stiffness (HQZS) mechanism, which is expected to break through the above bottleneck.
TL;DR: In this paper, the periodic nested acoustic black hole phononic structure is presented, and different complex band structures and corresponding evanescent Bloch wave propagation are discussed, which can be used in the vibration reduction design of lightweight structure and enrich the relevant research experience on acoustic black holes.
TL;DR: A concrete beam is a basic element for many applications in architectural engineering, and its vibration property plays an important role in safety and life-span as discussed by the authors, and previous vibration models were bas...
Abstract: A concrete beam is a basic element for many applications in architectural engineering, and its vibration property plays an important role in safety and life-span. Previous vibration models were bas...
TL;DR: In this article, the influence of the vibration parameter on the degree of undercooling and nucleation rate of the molten metals was investigated, and the experimental results showed that the grain size obtained under the application of ultrasonic vibration was finer than that obtained under condition of conventional laser cladding.
Abstract: Laser cladding has shown advantages in metal component forming. However, the accompanying issues, such as inner microstructural defects and poor mechanical properties, require further investigation. In this study, laser cladding technology was combined with ultrasound to improve the performance of the formed parts. Based on the cooperative effect of acoustic streaming and acoustic cavitation during the metal solidification process, the influence of the vibration parameter on the degree of undercooling and nucleation rate of the molten metals was investigated. The experimental results show that the grain size obtained under the application of ultrasonic vibration was finer than that obtained under condition of conventional laser cladding. When the amplitude was 25 μm, the average grain size was 0.522 times of that of non-vibration. The phase structure of the precipitates and the chemical composition changed markedly. In addition, the effects of high-frequency vibration on the mechanical properties of the cladding layer were also analysed through contrast experiments. The results indicate that applying high-frequency vibration can effectively reduce porosity, while improving the microhardness and wear resistance. Quantitatively, the friction coefficient was 0.628 times that without ultrasound and 0.709 times that of conventional processing when the amplitude was 25 μm.
TL;DR: In this article, an uncertain two-link rigid-flexible manipulator with vibration amplitude constraint is designed to achieve position control via motion planning and adaptive tracking approach, where the motion trajectories for the two links of the manipulator are planned based on virtual damping and online trajectories correction techniques.
Abstract: This article deals with an uncertain two-link rigid-flexible manipulator with vibration amplitude constraint, intending to achieve its position control via motion planning and adaptive tracking approach. In motion planning, the motion trajectories for the two links of the manipulator are planned based on virtual damping and online trajectories correction techniques. The planned trajectories can not only guarantee that the two links can reach their desired angles, but also have the ability to suppress vibration, which can be adjusted to meet the vibration amplitude constraint by limiting the parameters of the planned trajectories. Then, the adaptive tracking controller is designed using the radial basis function neural network and the sliding mode control technique. The developed controller makes the two links of the manipulator track the planned trajectories under the uncertainties including unmodeled dynamics, parameter perturbations, and persistent external disturbances acting on the joint motors. The simulation results verify the effectiveness of the proposed control strategy and also demonstrate the superior performance of the motion planning and the tracking controller.
TL;DR: In this paper, a vortex-induced vibration-based piezoelectric wind energy harvester using an indirectly excited composite transducer is investigated to enhance the reliability and environmental adaptability.
TL;DR: In this article, a nonlinear tribo-dynamic model of spur gear drives is established and experimentally validated in a helicopter design to improve survivability, when the gear drive loses lubrication due to battle damage.
TL;DR: In this paper, the authors investigated the coupled modeling method and free vibration characteristics of a graphene nanoplatelet (GPL) reinforced blade-disk rotor system in which the blade has a pre-twist angle and setting angle.
TL;DR: In this article, the impact of low-velocity impact on the electromechanical energy absorption capability and resonance frequency of the piezoelectric doubly curved panel on the viscoelastic substrate was investigated.
TL;DR: In this article, the first attempt to combine a quasi-zero-stiffness (QZS) mechanism and a triboelectric nanogenerator is made, and a QZS-TENG is devised.
TL;DR: In this article, the authors presented the smart control and frequency characteristics of a graphene nanoplatelets composite (GPLRC) cylindrical shell surrounded by piezoelectric layers as sensor and actuator (PLSA).
Abstract: In this article, smart control and frequency characteristics of a graphene nanoplatelets composite (GPLRC) cylindrical shell surrounded by piezoelectric layers as sensor and actuator (PLSA) are presented. The current structure is under an external load. For the semi-numerical method, the strain-stress relations can be determined through the first-order shear deformable theory (FSDT). For access to various mass densities as well as the Poisson ratio, the rule of the mixture is applied, although the modified Halpin-Tsai theory for obtaining the module of elasticity. The external voltage is applied to the sensor layer, while a Proportional-Derivative (PD) controller has been utilized for controlling the output of the sensor. The boundary conditions are derived through governing equations of the GPLRC cylindrical shell surrounded by PLSA using an energy method known as Hamilton's principle and finally are solved using a generalized differential quadrature method (GDQM). Apart from a semi-numerical solution, a finite element model was presented using the finite element package to simulate the response of the smart GPLRC cylindrical shell. The results created from a finite element simulation illustrates a close agreement with the semi-numerical method results. The outcomes show that the PD controller, viscoelastic foundation, slenderness factor (L/R), external voltage, and GPL's weight fraction have a considerable impact on the amplitude and vibration behavior of a GPLRC smart cylindrical shell. As an applicable result in related industries, the parameter and consideration of the PD controller have a positive effect on the static and dynamic behaviors of the structure subjected to an external load.
TL;DR: In this article, a dynamic model with four masses and 19 degree of freedoms was proposed to investigate the vibration response characteristics of an axial piston pump, where main parts are simplified by multiple lumped mass points connected with spring-damper elements.
TL;DR: The tuned mass damper is one of the most popular structural vibration suppression techniques as mentioned in this paper. But its performance has not yet reached the state-of-the-art of the art.
Abstract: To date, considerable attention has been paid to the development of structural vibration suppression techniques. Among all vibration suppression devices and techniques, the tuned mass damper is one...
TL;DR: Inspired by the flight mechanism of dipteran, a novel bionic-dipteran energy harvester (BDEH) was proposed to collect ultralow-frequency vibration energy as discussed by the authors.
TL;DR: In this paper, a rail-borne piezoelectric energy harvester was proposed to collect energy from the random railway vibration in a broad frequency range, and the fractional derivative electromechanical coupling model of the coupled vehicle-track-harvester system was firstly established.
TL;DR: In this article, the authors studied a vibration and disturbance rejection problem of a wind turbine tower under exogenous perturbations, where the tower dynamics were captured by a nonhomogeneous Euler-Bernoulli beam model.
Abstract: This paper studies a vibration and disturbance rejection problem of a wind turbine tower under exogenous perturbations. The tower dynamics is captured by a nonhomogeneous Euler-Bernoulli beam model. The dissipativity of the system is realized by a boundary feedback control solution with a multi-valued symbolic function. A Lyapunov-based stability analysis is established to assess that the deflection of the tower is uniformly bounded even subject to exogenous disturbances. The extended Filippov-framework and Galerkin approximation scheme are introduced to tackle the existence of the solution to the system with a discontinuous control input. Simulation results demonstrate the performance of the proposed control scheme.
TL;DR: An in-depth review of the different types of dynamic loads that may occur in concrete structures and special conditions that should be met to avoid the harmful effects of vibrations on concrete structures is presented.