Abstract

This paper focuses on analyzing the dynamic response of an innovated quasi-zero stiffness pneumatic vibration isolator (QZSPVI) using two mechanisms, including wedge and semicircle cam. Different from other studies relating quasi-zero stiffness isolation system, the pneumatic cylinder in this paper works as an air spring in order to easily adjust the dynamic stiffness of the proposed system according to the change of the isolated load through regulating the pressure. Firstly, the dynamic stiffness of the QZSPVI will be analyzed. Then, the condition for which the minimum dynamic stiffness is quasi-zero around the equilibrium position is also determined. The fundamental resonance response of the QZSPVI subjected to the externally harmonic force is analyzed through multi-scale method and the numerical simulations are verified. Secondly, due to exiting relative sliding frictional phenomenon between the cylinder and piston, instead of an experiment, another key content of this work is to identify the friction force model of the cylinder through virtual prototyping model. From this identified result, the complex dynamic response of the QZSPVI and coexistence of multiple solutions will be discovered by realizing the direct integration of the original dynamic equation through using the 5th-order Runge–Kutta algorithm. The analysis and simulation results clearly show the advantages of the proposed model against the equivalent pneumatic vibration isolator (EPVI), which only employs the wedge mechanism. This research will offer a useful insight into design and QZSPVI in practice.

Highlights

  • Xu et al [5] analyzed the dynamic response of quasi-zero stiffness isolator, as well as the jump-up and jump-down phenomenon of the amplitude–frequency curve

  • Motivated by the interest of the scientific community toward quasizero stiffness vibration systems and promising application, authors developed and realized the static analysis of a quasi-zero stiffness pneumatic vibration isolator (QZSPVI) [31] in which a pneumatic cylinder with an auxiliary tank worked as an elastic element, revealing that the stiffness curve of the isolator is asymmetrical around the desirable equilibrium position

  • The vertical force which acts on the load plate is only caused by the load-bearing structure, whilst the arbitrary state is determined when the load plate moves away from the equilibrium position at distance u < Ho, at which the load plate will be acted on by two vertical forces generated by both the load-bearing mechanism (LBM) and stiffness correction mechanism (SCM)

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Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Zhou et al [7] built and analyzed the nonlinear dynamic model of a prototype of quasi-zero stiffness (QZS) vibration isolation model with cam-roller-spring, obtaining an effective isolation response at low frequency bands. Motivated by the interest of the scientific community toward quasizero stiffness vibration systems and promising application, authors developed and realized the static analysis of a quasi-zero stiffness pneumatic vibration isolator (QZSPVI) [31] in which a pneumatic cylinder with an auxiliary tank worked as an elastic element, revealing that the stiffness curve of the isolator is asymmetrical around the desirable equilibrium position This asymmetry can effect the amplitude–frequency response as well as the dynamic behavior of the isolator.

Description
Stiffness Analysis
Ho tan α dFSCM n
Primary Frequency—Amplitude Relation
Transmissibility for Force Excitation
Influence of Parameters on the Force Transmitted Curve
Complex Dynamic Response
Findings
Conclusions
Full Text
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