High-static-low-dynamic-stiffness vibration isolation enhanced by damping nonlinearity

Abstract

High-static-low-dynamic-stiffness (HSLDS) nonlinear isolators have proven to have an advantage over linear isolators, because HSLDS nonlinear isolators allow low-frequency vibration isolation without compromising the static stiffness. Previously, these isolators have generally been assumed to have linear viscous damping, degrading the performance of the isolator at high frequencies. An alternative is to use nonlinear damping, where the nonlinear behavior is achieved by configuring linear dampers so they are orthogonally aligned to the excitation direction. This report compares the performances of single-stage and two-stage isolators with this type of damping with the corresponding isolators containing only linear viscous damping. The results show that both isolators with linear viscous damping and nonlinear damping reduce the transmissibility around the resonance frequencies, but the results show that the isolators with nonlinear damping perform better at high frequencies.

The Elliptic Harmonic Balance Method for the Performance Analysis of a Two‐Stage Vibration Isolation System with Geometric Nonlinearity

“…is two-stage nonlinear isolation system extends the frequency range of isolation to low frequencies [13]. Furthermore, as shown in Figures 3-6, the values of the relative amplitude between upper and lower stages in the resonance region are at a similar level, but in the high frequency region, the isolation performance of the lower stage is better than that of the upper stage.…”

“…It can be seen that the solution of the EHBM can be compared well with the numerical results. More detailed analyses of the force transmissibility are given in [11][12][13][14][15].…”

“…Many of them have the configuration of geometrically nonlinear springs [3][4][5] and dampers [6][7][8] whose arrangement can obtain low dynamic stiffness, thereby reducing the natural frequency without inducing large static deflection [9,10]. Furthermore, two-degree-of-freedom (2-DOF) vibration isolation systems with quasi-zero-stiffness (QZS) and geometrically nonlinear damping have been studied [11][12][13][14]. Lu et al showed that both the force and displacement transmissibilities are mitigated in the isolation range as the horizontal stiffnesses in both stages are increased [11].…”

Design and test of an adjustable quasi-zero stiffness device and its use to suspend masses on a multi-modal structure

“…Some common applications for these devices include vibration isolation, vibration absorbers and vibration energy harvesters [2]. Perhaps the most widespread use of nonlinear stiffness elements has been in vibration isolation [3][4][5][6][7][8][9][10][11], but they are also being considered for inclusion in metamaterials to adjust band gap performance [12], and similar principles are also exploited in energy harvesting [13]. However, in this paper, the application of interest is in static loading a structure using masses suspended from the structure using QZS devices.…”

High‐Efficiency Vibration Isolation for a Three‐Phase Power Transformer by a Quasi‐Zero‐Stiffness Isolator

“…In the past few years, various configurations of the QZS isolator [18][19][20][21][22] and nonlinear spring [23,24] have been proposed and studied. Xu et al [25] and Wang et al [26] developed a QZS isolator by utilizing the inclined springs to realize the negative-stiffness mechanism and using the vertical spring to support the payload.…”