反共振双层隔振系统分析

Analysis of anti-resonant two-stage isolation system

提出以反共振隔振方法进行双层隔振系统设计,在不降低隔振区传递率衰减速率的条件下,抑制共振峰值改善双层隔振性能。针对三型单惯容反共振隔振器(anti-resonant vibration isolator,AVI),进行了结构选型分析,优选了二级串联型三元件反共振隔振器用于双层隔振系统;基于传递曲线存在与阻尼无关的固定点性质,建立了反共振双层隔振系统的调谐优化方法;考虑了反共振隔振器作为上层和下层隔振装置两种情形,根据所建立的优化方法分别得到了两种情形下刚度比和阻尼比的优化数值解,分析了调谐状态下共振峰值关于质量比的变化规律,最后讨论了传统隔振器(conventional vibration isolator,CVI)阻尼的影响。结果表明:反共振隔振器在共振区有效抑制共振峰值,在隔振区保持双层隔振传递率衰减速率;共振峰值与质量比成负相关性;传统隔振器阻尼对反共振隔振效果不产生实质影响,但改变隔振区传递率衰减速率。

Here,the anti-resonant vibration isolation(AVI)method was proposed to design a two-stage isolation system,this system could suppress resonance peak and improve two-stage isolation performance under the condition of not reducing the decay rate of transmissibility in vibration isolation region.The structure type-choosing analysis was performed for three types of single inerter anti-resonant vibration isolator,a two-stage series 3-element anti-resonant vibration isolator was selected,it could be suitable for two-stage isolation system.Based on the transmission curve having fixed point property not related to damping,the tuning optimization method of anti-resonant two-stage isolation system was established.Considering two cases of anti-resonant vibration isolator taken as upper layer vibration isolation device and lower layer one,optimal numerical solutions to the system’s stiffness ratio and damping ratio in these two cases were obtained,respectively according to the established optimization method,and variation laws of resonance peak versus mass ratio in tuning state were analyzed.Finally,effects of conventional vibration isolator(CVI)damping were discussed.The results showed that the anti-resonant vibration isolator can effectively suppress resonance peak in resonance region and keep the decay rate of transmissibility of two-stage isolation in vibration isolation region;resonance peak is negatively correlated to mass ratio;conventional vibration isolator damping has no substantial influence on anti-resonant vibration isolation effect,but it changes the decay rate of transmissibility in vibration isolation region.