偏载作用下菱形负刚度隔振系统的刚度特性

Stiffness Characteristics of Rhombic Negative Stiffness Vibration Isolation System Under Unbalance Loading

为探究偏载对菱形负刚度隔振系统刚度的影响,课题组基于力学分析方法,建立了偏载作用下隔振系统的数学模型,得到其无量纲刚度-位移非线性曲线,分析了偏载对其准零刚度特性的影响。利用Simulink进行仿真实验,给偏载作用下的隔振系统振动基座施加激励,得到了不同激励下隔振系统的时变刚度;结合傅里叶变换,探讨了隔振系统刚度的时变特性和幅频特性。结果表明:偏载越大,低刚度区间越窄,准零刚度特性越弱;时变刚度波动范围与峰值随偏载的增加而变大,但时变刚度的波动趋势不受偏载的影响;时变刚度幅值主要集中在低频区间,随频率的增加而减小,最终趋近于0。研究表明偏载对隔振系统的刚度会产生一定的影响。

In order to study the effect of unbalance loading on the stiffness of rhombic negative stiffness vibration isolation system,based on the mechanical analysis method,the mathematical model of the vibration isolation system under unbalance loading was established,the dimensionless stiffness-displacement nonlinear curves were obtained,and the influence of unbalance loading on its quasi-zero stiffness characteristics was analyzed.Simulation experiments were carried out using simulink to apply excitation to the vibration base of the vibration isolation system under unbalance loading,and the time-varying stiffness of the vibration isolation system under different excitations was obtained.Combined with Fourier transform,the time-varying and amplitude-frequency characteristics of the stiffness of the vibration isolation system were discussed.The results show that the higher the unbalance loading,the narrower the low stiffness interval and the weaker the quasi-zero stiffness characteristic.The fluctuation range and peak value of the time-varying stiffness increase larger with the increase of unbalance loading,but the fluctuation trend of the time-varying stiffness is not affected by unbalance loading.The amplitude of the time-varying stiffness is mainly concentrated in the low-frequency interval,which decreases with the increase of the frequency,and eventually approaches 0.Stiffness of the vibration isolation system will be influenced by unbalance loading.