菱形HSLDS隔振器负刚度机构质量及摩擦力影响分析

Analysis of mass and friction effect of negative stiffness mechanism of rhombic HSLDS vibration isolator

以菱形负刚度机构HSLDS(high static low dynamic stiffness)隔振器(简称菱形HSLDS隔振器)为研究目标,采用虚功法建立负刚度机构等效摩擦力模型,并以拉格朗日方法建立包含负刚度机构质量及摩擦力因素的动力学方程;利用谐波平衡法(HBM)求解动力学方程,分析了负刚度机构质量及摩擦力对隔振的影响及其优化措施,并通过实物样机验证了理论模型的合理性。实验结果表明:负刚度机构质量及摩擦力对隔振均产生不利影响,应尽量减小;将负刚度机构连杆较短侧连接于载荷平台端,可以减小负刚度机构质量对较高频段隔振性能的影响;在限定隔振器刚度参数以及铰接副接触参数且同时满足刚度与摩擦力优化条件下,通过增大连杆机构杆长差的方式可以优化低频段隔振性能,并降低负刚度机构摩擦力对高频段隔振的影响。

Taking high static low dynamic stiffness(HSLDS)vibration isolator with rhombic negative stiffness mechanism(rhombic HSLDS isolator)as research object,the equivalent friction model of negative stiffness mechanism was established by virtual work method,and the kinetic equation with factors of negative stiffness mechanism mass and friction was established by Lagrange method.The kinetic equation was solved by harmonic balance method(HBM),the influences of negative stiffness mechanism mass and friction on vibration isolation and optimization measures were analyzed,and the rationality of theoretical model was verified by the prototype.The experimental results show that the mass and friction of negative stiffness mechanism have adverse effect on vibration isolation and should be reduced.Connecting the shorter rod side of negative stiffness mechanism to the end of load platform can reduce influence of the negative stiffness mechanism mass on vibration isolation performance in higher-frequency range.Under condition that stiffness parameters of isolator and contact parameters of hinged pairs are fixed,and the stiffness and friction are satisfied simultaneously,the vibration isolation performance in low-frequency range can be optimized by increasing the rod length difference,and can reduce the influence of negative stiffness mechanism friction on vibration isolation in high-frequency range.