A study of the vibration isolation performance of a limited phononic crystal vibration isolator based on local resonance theory

2020 ◽  
Vol 128 (13) ◽  
pp. 134903
Author(s):  
Caiyou Zhao ◽  
Xin Gao ◽  
Liuchong Wang ◽  
Qiang Yi ◽  
Ping Wang
Keyword(s):  
Vibration Isolation ◽  
Phononic Crystal ◽  
Vibration Isolator ◽  
Resonance Theory ◽  
Local Resonance ◽  
Vibration Isolation Performance ◽  
Isolation Performance

scholarly journals An Asymmetric Quasi-zero Stiffness Vibration Isolator with Long Stroke and Large Bearing Capacity

2021 ◽  
Author(s):  
Xinghua Zhou ◽  
Dingxuan Zhao ◽  
Xiao Sun ◽  
Xiao Yang ◽  
Jianhai Zhang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Vibration Isolation ◽  
Geometrical Nonlinearity ◽  
Harmonic Balance Method ◽  
Nonlinear Damping ◽  
Vibration Isolator ◽  
Plate Spring ◽  
Supporting Force ◽  
Vibration Isolation Performance ◽  
Isolation Performance

Abstract A novel passive asymmetric quasi-zero stiffness vibration isolator (AQZS-VI) comprising two linear springs acting in parallel with one negative stiffness element (NSE) is proposed, of which the NSE is mainly constructed by the combination of cantilever plate spring and L-shaped lever (CPS-LSL). The static model of the isolator is deduced considering the geometrical nonlinearity of the NSE and the bending deformation of plate spring. The nonlinear stiffness properties of the CPS-LSL and the AQZS-VI, as well as the nonlinear damping properties of the AQZS-VI are discussed. The absolute displacement transmissibility of the AQZS-VI under base displacement excitation is obtained using Harmonic Balance Method, and the effects of different excitation amplitudes and damping factors on the vibration isolation performance are analyzed. Better than other quasi-zero stiffness vibration isolators (QZS-VI) whose NSEs do not provide supporting force at zero stiffness point, the NSE of the AQZS-VI provides more supporting force than the parallel connected linear springs, which is very beneficial for improving the bearing capacity of the isolator. Compared with a typical symmetric QZS-VI with same damping property, the AQZS-VI has longer stroke with low stiffness and lower peak value of displacement transmissibility. The prototype experiments indicate that the AQZS-VI outperforms the linear counterpart with much smaller starting frequency of vibration isolation and lower displacement transmissibility. The proposed AQZS-VI has great potential for applying in various engineering practices with superior vibration isolation performance.

A composite aperiodicity elastic vibration isolator containing local resonator

2020 ◽  
pp. 2050430
Author(s):  
Xiaofei Lei ◽  
Nan Wu ◽  
Peng Chen ◽  
Heping Hou ◽  
Shanhui Liu ◽  
...  
Keyword(s):  
Frequency Band ◽  
Power Distribution ◽  
Vibration Isolation ◽  
Transmission Ratio ◽  
Total Power ◽  
Resonance Structure ◽  
Local Resonance ◽  
Vibration Wave ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The transmission of vibration waves in specific frequency bands can be suppressed by the local resonance and the multi-layer transmission structure. A composite non-periodic isolator containing a local resonance structure is proposed in this paper. The transmission performance of vibration waves is studied using the modal displacement, and the main vibration control frequency band is picked up for vibration wave transmission. Meanwhile, the total power distribution, frequency quality loss factor and total power loss density are calculated in main frequency band. Further, the energy transmission and loss performance of vibration waves are studied in the composite non-periodic isolator. The transmission ratio of the vibration wave is also discussed, the evolution of the vibration transmission ratio is compared in each metal frame of the composite non-periodic isolator, and the vibration isolation performance is evaluated. Research shows that the vibration isolation energy can be effectively increased and the vibration isolation performance can be effectively improved in the proposed composite non-periodic isolator.

scholarly journals Design and Research of Semiactive Quasi-Zero Stiffness Vibration Isolation System for Vehicles

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Shaohua Li ◽  
Guizhen Feng ◽  
Quan Zhao
Keyword(s):  
Embedded System ◽  
Vibration Isolation ◽  
Test System ◽  
Isolation Effect ◽  
Vertical Acceleration ◽  
Vibration Isolator ◽  
Isolation System ◽  
Labview Software ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vehicle-mounted equipment is easy to be disturbed by external vibration excitations during transportation, which is harmful to the measurement accuracy and performance of the equipment. Aiming at the vibration isolation of the vehicle-mounted equipment, a semiactively controlled quasi-zero stiffness (QZS) vibration isolator with positive and negative stiffness is proposed. The vertical spring is paralleled with a magnetorheological (MR) damper, and the semiactive on-off control scheme is adopted to control the vibration. The analytical expression of the isolator’s displacement transmissibility is derived via the averaging method. Then, the vibration isolation performance under different road excitations and different driving speeds is simulated and compared with the uncontrolled passive QZS vibration isolator. In addition, the mechanical structure of the semiactive QZS isolator is designed and manufactured, and the test system is built by LabVIEW software and PXI embedded system. The isolation effect of the semiactive QZS isolator is verified through test data. It is found that the proposed semiactive QZS isolator shows excellent vibration isolation performance under various road excitations, while the passive QZS isolator is effective only under harmonic excitations. The vertical acceleration of vehicle-mounted device can be decreased over 70% after isolation, and the vibration isolation effect is remarkable. The design idea and research results of the semiactive QZS isolator may provide theoretical guidance and engineering reference for vibration isolation.

scholarly journals A Vibration Isolation System Using the Negative Stiffness Corrector Formed by Cam-Roller Mechanisms with Quadratic Polynomial Trajectory

2020 ◽  
Vol 10 (10) ◽  
pp. 3573 ◽  
Author(s):  
Mengnan Sun ◽  
Zhixu Dong ◽  
Guiqiu Song ◽  
Xingwei Sun ◽  
Weijun Liu
Keyword(s):  
Vibration Isolation ◽  
Quadratic Polynomial ◽  
Negative Stiffness ◽  
Calculation Error ◽  
Vibration Isolator ◽  
Isolation System ◽  
Frequency Wave ◽  
Vibration Isolation System ◽  
Vibration Isolation Performance ◽  
Isolation Performance

The vibration isolator equipped with a negative stiffness corrector (NSC) excels at vibration isolation, but its stiffness often presents complex nonlinearity which needs to be approximated in calculation. To avoid the harmful effects of approximate stiffness, the NSC formed by the cam-roller mechanism with a quadratic polynomial trajectory (QCRM) is proposed to construct the vibration isolation system. From the inherent geometrical relationship in the structure, the generation mechanism of high-static-low-dynamic stiffness is analyzed, and the quasi-zero stiffness (QZS) condition of the system is derived. Based on the dynamic model of the QZS vibration isolator, the functions of response characteristics are solved by the harmonic balance method. Then, the absolute displacement transmissibility with different parameter values, and the vibration isolation performance under sinusoidal, multi-frequency wave, and random excitations are discussed. The simulated results show that the stiffness expression of the proposed QZS vibration isolator is directly a quadratic function, which removes the calculation error caused by approximate stiffness at large displacement and broadens the available isolation displacement range. Introducing the QCRM-NSC can significantly suppress the low-frequency vibration and resonance response without changing the load-bearing capacity of the vibration isolator. Under various excitations, the vibration isolation performance of the QZS vibration isolator all outperforms the linear counterpart.

Vibration control of an unbalanced system using a quasi-zero stiffness vibration isolator with fluidic actuators and composite material: An experimental study

2022 ◽  
pp. 107754632110514
Author(s):  
Sivakumar Solaiachari ◽  
Jayakumar Lakshmipathy
Keyword(s):  
Composite Material ◽  
Nonlinear Vibration ◽  
Vibration Isolation ◽  
Basalt Fiber ◽  
Experimental Investigations ◽  
Vibration Isolator ◽  
Coil Spring ◽  
Linear Type ◽  
Fluidic Actuators ◽  
Isolation Performance

In this study, a new type of vibration isolator based on fluidic actuators and a composite slab was tested experimentally with an unbalanced disturbance. Quasi-zero stiffness vibration isolation techniques are advanced and provide effective isolation performance for non-nominal loads. The isolation performance of the proposed isolator was compared to that of a nonlinear vibration isolator equipped with fluidic actuators and a mechanical coil spring (NLVIFA). The NLVIFA system is better suited to non-nominal loads; however, the mechanical spring axial deflection leads to limited amplitude reduction in the system. To address this issue, a cross buckled slab was developed to replace a mechanical coil spring for absorbing vertical deflection by transverse bending, which is made of a specially developed composite material of Basalt fiber reinforced with epoxy resin and enhanced with graphene nano pellets. This current study was concerned with the theoretical analysis and experimental investigations of the proposed nonlinear vibration isolator with fluidic actuators and composite material (NLVIFA-CM), which performs under quasi-zero stiffness characteristics. Because of its reduced axial deflection, the theoretical and experimental results show that the NLVIFA-CM system outperforms the NLVIFA system and other linear type vibration isolators in terms of isolation performance. Furthermore, the proposed vibration isolator makes a significant contribution to low-frequency vibration.

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