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.
Highlights
Mechanical vibration is undesirable in most engineering practice
(NSE) is proposed, of which the negative stiffness element (NSE) is mainly constructed by the combination of cantilever plate spring and L-shaped lever (CPS-LSL)
A typical vibration isolator comprising two oblique springs acting in parallel with one vertical spring studied in the literatures [12] and [13] is chosen as the symmetric QZS-VI (SQZS-VI) for 665 comparison
Summary
Mechanical vibration is undesirable in most engineering practice. It affects the mechanical properties, aggravates wear and fatigue, and even causes structural damage. Nonlinear passive vibration isolators, possessing high static and low dynamic stiffness (HSLDS) and nonlinear damping properties, are suitable for low or ultra-low frequency isolation. A series of researches reveal that the passive QZS-VIs can produce lower starting frequency of vibration isolation and smaller displacement/force transmissibility than the linear counterparts. The scissor-like structured isolators possessing inherent geometrical nonlinearities have lower starting frequency of isolation than linear isolators and are more stable than QZS-VIs. While, for the single nonlinear geometrical vibration isolators, it is not easy to realize ultra-low frequency vibration isolation for that its dynamic stiffness is hard to approach zero. An asymmetric quasi-zero stiffness vibration isolator (AQZS-VI) constructed by single nonlinear geometrical vibration isolator and positive stiffness springs is expected to obtain excellent vibration isolation performance with large bearing capacity, low stiffness in wide displacement range, i.e., long stroke, and ultra-low frequency isolation.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
