柔性双层隔振系统振动能量解耦方法及应用

Vibration Energy Decoupling Method and Application for Flexible Double-Layer Vibration Isolation Systems

为解决难以利用能量解耦法设计柔性双层隔振系统的问题,提出一种能够表示柔性设备和中间质量弹性模态特点的多自由度模型;基于该模型,提出采用广义弹性力对柔性隔振系统进行解耦的方法,并推广到柔性结构中;以某内燃动车动力总成双层隔振系统为例,基于所提方法探讨了构架弹性模态下刚体振动与弹性振动的耦合情况;最后通过振动实验台验证了该方法的有效性.研究结果表明:机组一级隔振系统垂向频率从12 Hz降低到8 Hz后,系统所有模态频率均得到不同幅度的下降,前两阶刚体振动模态频率下降最明显,分别下降50.00%和49.98%;构架弹性模态频率比机组弹性模态频率更低,影响更大,构架弹性模态频率下降8.32%,机组弹性模态频率下降0.80%;在构架弹性振动模态振动中,构架弹性振动能量所占比例提高14.88%,刚体振动能量所占比例降低90.64%,降低一级隔振系统垂向频率能够提高振动解耦效果,减少振动传递.

The original energy decoupling method is not suited to flexible double-layer vibration isolation systems,and therefore a multi-degree of freedom model is developed to represent the flexible characteristics of the equipment and intermediate mass.Then,on the basis of the model,a generalized elastic force is proposed to decouple the flexible vibration isolation system.The decoupling method is then extended to the study of flexible structures.Finally,using a two-layer vibration isolation system of a powertrain as an example,the method is adopted to evaluate the decoupling performance of the elastic mode of the frame.Finally,a vibration test was used to verify the effectiveness of this method.The results show that after the primary vertical frequency of the powerpack decreases from 12 Hz to 8 Hz,all of the modal frequencies of the system are reduced by different extents.The first two order frequencies of the rigid body vibration modes decreased by 50.00%and 49.98%,respectively.The elastic modal frequency of the frame has a greater impact because of its lower natural frequency compared with that of the diesel generator set.The elastic modal frequency of the frame decreased by 8.32%,and that of the diesel generator set decreased by 0.80%.In the elastic vibration mode vibration of the frame,the proportion of the elastic vibration energy of the frame could increase by 14.88%,and the proportion of the rigid body vibration energy could be reduced by 90.64%.Reducing the vertical frequency of the first stage vibration isolation system can improve the vibration decoupling effect and reduce the vibration transmission。