新型低频隔振器的特性研究

Characteristics of a novel low-frequency isolator

通过并联具有负刚度特性的刀口支撑滑动梁和正刚度的线性弹簧,设计了全新型的超低频非线性隔振系统。分析了系统的静态力学特性,给出了系统的力-位移关系以及刚度曲线,系统的非线性特性明显。求取了系统具有近似动态零刚度时的参数配置并结合实际应用选定了系统工作平衡点。建立了系统的非线性动力学方程,在对方程进行简化后,采用谐波平衡法求解了Helmholtz-Duffing方程的响应,分析了系统的频响特性,得出了在激励幅值较小的激励下系统具有渐软特性,而激励幅值增大后系统会出现二次跳变,即先表现为软特性后表现为硬特性。对此种新型隔振器的设计提供了理论指导。

Combining parallelly a knife-supported sliding beam featured negative stiffness with a linear positive stiffness mechanical spring, a fully new type ultra-low frequency passive isolator was proposed and designed here. The static characteristics of the system were analyzed, the displacement-force relationship the stiffness curve were given. The system configuration possessing quasi-zero dynamic stiffness was derived. The equilibrium operation point was selected considering the practical application. The nonlinear dynamic equation was established and solved using harmonic balance method （HBM） after appropriately simplifying it to a Helmholtz-Duffing equation. The system behaved softening feature under excitaions with small amplitude. And a double-jump phenomenon was found with excitation amplitude growing, i. e. , the dynamic characteristic of the system changed from softening feature to hardening one. The results offered a theoretical guidance for design of such a kind of low-frequency nonlinear isolator.