隔振对象重量变化对准零刚度隔振器隔振性能的影响

EFFECT OF LOAD IMPERFECTION ON VIBRATION ISOLAITON PERFORMANCE OF A QUASI-ZERO-STIFFNESS ISOLATOR

本文主要研究隔振对象重量变化对一类准零刚度隔振器隔振性能的影响,并给出了新的研究结果.文中使用欧拉屈曲梁构建负刚度调节结构并设计了隔振系统的平衡位置可调机构.假设系统有轻微的过载和超载,推导了系统的动力学方程并进行求解,定义了非线性隔振系统的力传递率及位移传递率来评价系统的隔振性能.对线性隔振系统,超载会让隔振频率略微降低,共振放大峰略微增大.对于准零刚度隔振系统,力传递率和线性系统类似,但是对于位移传递率,过载会导致系统固有频率和共振放大峰均升高,反而不利于隔振.研究结果可以对此类隔振系统的使用场合以及对过载和轻载的选择有工程指导意义.

A quasi-zero-stiffness(QZS)isolator was configured by combining an Euler buckled beam negative stiffness corrector and a linear isolator.Making the load balanced at the zero-stiffness point,the QZS isolator can offer ultra-low frequency vibration isolation performance.However,overload or underload usually happens in practices.This paper in⁃restigated the effects of load imperfection on the performance of the QZS isolator by using force and displacement trans⁃missibility,which was also compared with the linear isolator.Assuming slight overload or underload and adjusting the ac⁃tual load to the zero-stiffness position for the QZS isolator,the dynamic response of the vibration isolation system was ob⁃tained by using the harmonic balance method.For the linear system,the resonant frequency decreases and the peak transmissibility increases under overload.In the case of force transmissibility,the QZS system is similar to the linear sys⁃tem.However,the displacement transmissibility is opposite.Increasing load makes both the peak and resonance frequen⁃cy of the absolute and relative displacement transmissibility shift to higher values.The results presented here can be a useful guideline when design such a kind of vibration isolator.