scholarly journals A piecewise negative stiffness mechanism and its application in dynamic vibration absorber

2021 ◽  
Vol 1 (2) ◽  
pp. 173-181
Author(s):  
Yan Hao ◽  
Yongjun Shen ◽  
Junfeng Wang ◽  
Shaopu Yang
Keyword(s):  
Negative Stiffness ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Negative Stiffness Mechanism

Controlling the vibration and noise of a ballasted track using a dynamic vibration absorber with negative stiffness

2019 ◽  
Vol 234 (10) ◽  
pp. 1265-1274
Author(s):  
Haiping Liu ◽  
Dongmei Zhu
Keyword(s):  
Decay Rate ◽  
Negative Stiffness ◽  
Design Parameters ◽  
Vibration Energy ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Radiated Noise ◽  
Dynamic Vibration ◽  
Track System ◽  
Ballasted Track

In this study, a rail dynamic vibration absorber with negative stiffness is developed to reduce the vibration transmission and radiated noise from the rail components of a ballasted track. The compound models of the ballasted track system with and without the proposed dynamic vibration absorber and a traditional dynamic vibration absorber are constructed. A parametric study is performed to evaluate the effects of the design parameters of the proposed dynamic vibration absorber on the vibration and noise reduction of the track system in terms of the point receptance, the decay rate of rail vibration along the track, and the vibration energy level of the rail. Compared with the traditional dynamic vibration absorber, the proposed counterpart can work effectively over a broad frequency range around resonance. The efficiency of the dynamic vibration absorber can be improved by adjusting the design values of the active mass and damping coefficient. A comparison with the traditional dynamic vibration absorber shows that the vibration and noise suppression capability of the proposed one can be enhanced by increasing the value of the stiffness ratio. However, different from the traditional dynamic vibration absorber, the design parameters of the proposed one can also affect the decay rate and vibration energy at low-frequency regions. A discrete track with the proposed dynamic vibration absorber, which is arranged in continuous or discrete distribution along the rail, is illustrated to study the influences of the rail components on the decay rate and vibration energy level of rails. These calculated results could provide a theoretical basis for the design of the proposed dynamic vibration absorber in controlling the vibration and radiated noise from rails.

scholarly journals H∞ optimization of Maxwell dynamic vibration absorber with multiple negative stiffness springs

2020 ◽  
pp. 146134842097281
Author(s):  
Yan Hao ◽  
Yongjun Shen ◽  
Xianghong Li ◽  
Jun Wang ◽  
Shaopu Yang
Keyword(s):  
Fixed Point Theory ◽  
Damping Ratio ◽  
Negative Stiffness ◽  
System Stability ◽  
Vibration Absorber ◽  
Primary System ◽  
Stiffness Ratio ◽  
Dynamic Vibration Absorber ◽  
System Parameters ◽  
Dynamic Vibration

The Maxwell model with viscoelastic material and multiple negative stiffness springs is introduced into dynamic vibration absorber system, and all the system parameters are optimized in detail. The analytical solution of the primary system is exhibited according to the established motion differential equation. The dimensionless system parameters, including the optimum natural frequency ratio, the optimum damping ratio and the first optimum negative stiffness ratio of dynamic vibration absorber, are obtained based on H∞ optimization principle and the fixed-point theory. Considering system stability, the other optimum negative stiffness ratio is also determined. Furthermore, by the comparisons of the presented dynamic vibration absorber with other traditional dynamic vibration absorbers, it is found that the dynamic vibration absorber in this paper has better vibration reduction effect in the case of both harmonic and random excitation.

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