An improved quasi-zero stiffness isolator with two pairs of oblique springs to increase isolation frequency band

Zhao, Feng; Ji, Jinchen; Luo, Quantian; Cao, Shuqian; Chen, Lumin; Du, Wenliao

doi:10.1007/s11071-021-06296-4

Cited by 69 publications

(20 citation statements)

References 37 publications

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“…e system is excited at its base (the casing) by an imposed displacement y, as illustrated in Figure 1(b), so that the suspended mass can oscillate inside its casing. A viscous damper c is introduced as a generic dissipative term, which is a practical assumption validated by some recent experimental works on similar suspension configurations [17][18][19]. e relative displacement between the mass and the casing is indicated by z, so that when z = 0 the mass is located at the centre of the casing.…”

Section: Force-deflection Characteristicmentioning

confidence: 99%

“…In this paper, a softening-hardening behaviour is achieved by simply arranging linear springs in an X-shaped mechanical configuration, realizing a quasi-zero stiffness effect for large deflections. Following the preliminary idea presented in [16], a series of research works have recently addressed its exploitation to develop innovative vibration isolators [17][18][19], and it is believed that such characteristic may be of interest to other applications, so that it is further studied in this paper.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Parameters on the Design of a Suspension System with Four Oblique Springs

Gatti

2021

Shock and Vibration

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This paper presents the fundamental static and dynamic characteristics of a suspension system consisting of four linear springs arranged in an X-shaped configuration to achieve geometric nonlinearity. The particular interest is towards the design of a softening spring geometry realizing a quasi-zero stiffness behaviour at large deflections, and the influence of the system parameters is investigated. The static performance is studied in terms of the force-deflection curve and the dynamic performance in terms of the frequency response curve. The softening-hardening behaviour of the suspension leads to a frequency response which bends to the lower frequencies reaching a well-defined minimum. It is found that both the static and dynamic behaviours may be described in terms of a single parameter, and a simple closed-form expression is determined which links the damping in the system to the excitation amplitude to achieve the lowest possible resonance frequency.

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Section: Force-deflection Characteristicmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Parameters on the Design of a Suspension System with Four Oblique Springs

Gatti

2021

Shock and Vibration

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“…Equation (10) indicates that the geometric parameter c is contained in the expression of the natural frequency with respect to the nondimensional stiffness. To achieve expected performance, the natural frequency of the isolator should be constrained during operation.…”

Section: Optimization Criteria For Qzs Mechanismmentioning

confidence: 99%

“…e nondimensional movement range of the isolator 􏽢 d f at the critical natural frequency f c is twice the value of 􏽢 x d . By substituting equations (10) and (11) into equation ( 5), its expression can be written as follows:…”

Section: Optimization Criteria For Qzs Mechanismmentioning

confidence: 99%

“…A bioinspired nonlinear system with four linear springs arranged in a K-shaped configuration was proposed for the purpose of potential energy maximization [8]. Zhao et al [9][10][11] proposed new limb-like QZS systems with two pairs and three pairs of oblique springs to enlarge the QZS range and isolation frequency band. Similarly, Yan et al [12] proposed a large stroke QZS vibration isolator using a three-link mechanism, which is less sensitive to vibration amplitude than the traditional QZS isolator.…”

Section: Introductionmentioning

confidence: 99%

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An Improved Structural Analysis Method for Isolator with Quasi‐Zero‐Stiffness Characteristic

Zhang

et al. 2021

Shock and Vibration

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A typical quasi-zero-stiffness (QZS) vibration isolator consisting of a vertical spring and two oblique springs has been widely researched on its static and dynamic characteristics. A general criterion for determining structural parameters of QZS isolator is to achieve low nondimensional stiffness around the equilibrium position. However, lower nondimensional stiffness of linear isolator means lower isolation frequency, which may be invalid on QZS isolator. Because there is an implicit relationship between geometric parameter and stiffness ratio of QZS isolator, this study presents an improved optimization criterion for determining the optimal structural parameters of the typical QZS isolator. The optimization criterion is that the QZS isolator has the maximum displacement range around the equilibrium position without exceeding given natural frequency, rather than given nondimensional stiffness. The results show that isolator with these optimal parameters can achieve lower stiffness around the equilibrium position and better vibration isolation performance. Furthermore, an extended QZS isolator consisting of vertical spring with fixed stiffness and prestressed oblique springs is discussed to further improve stiffness characteristic. Better stiffness performance can be obtained when the prestressed oblique springs have softening stiffness and the exponent of the nonlinear stiffness is 2. Considering the existence of friction in practical application, the influence of friction on both static and dynamic characteristics is investigated. The analysis reveals that friction has little influence on its stiffness characteristic around the static equilibrium position and friction damping produced by friction affects the response amplitude and resonant frequency in dynamics.

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Three‐magnet‐ring quasi‐zero stiffness isolator for low‐frequency vibration isolation

Wang,

Hou,

Meng

et al. 2024

Int Journal of Mech Sys Dyn

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A three‐magnet‐ring quasi‐zero stiffness (QZS‐TMR) isolator is designed to solve the problem of low‐frequency vibration isolation in the vertical direction of precision equipment. QZS‐TMR has both positive and negative stiffness structures. The positive stiffness structure consists of two mutually repelling magnetic rings and the negative stiffness structure consists of two magnetic rings nested within each other. By modulating the relative distance between positive and negative stiffness structures, the isolator can have QZS characteristics. Compared with other QZS isolators, the QZS‐TMR is compact and easy to manufacture. In addition, the working load of QZS‐TMR can be flexibly adjusted by varying the radial widths of the inner magnetic ring. In this paper, the static analysis of QZS‐TMR is carried out to guide the design, and the low‐frequency vibration isolation performance is studied. In addition, the experimental prototype of QZS‐TMR is designed and manufactured. The static and vibration isolation experiments are carried out on the prototype. The results show that the initial vibration isolation frequency of the experimental prototype is about 4 Hz. The results show an excellent low‐frequency vibration isolation effect, which is consistent with the theoretical research. This paper introduces a new approach to the design of the QZS isolator.

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An improved quasi-zero stiffness isolator with two pairs of oblique springs to increase isolation frequency band

Cited by 69 publications

References 37 publications

Effect of Parameters on the Design of a Suspension System with Four Oblique Springs

Effect of Parameters on the Design of a Suspension System with Four Oblique Springs

An Improved Structural Analysis Method for Isolator with Quasi‐Zero‐Stiffness Characteristic

Three‐magnet‐ring quasi‐zero stiffness isolator for low‐frequency vibration isolation

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