设备安装对基座导纳测量的影响研究

裸基座导纳是隔振设计的重要参数.工程中常需要在设备安装状态下测量基座的导纳,这会给基座导纳测量带来误差.本文针对单个安装点的情况(低频时成立)从理论上证明了这种误差在某些条件下是可以忽略的,即设备刚性安装时基座阻抗应远大于设备机脚阻抗;弹性安装时若基座阻抗远大于隔振器阻抗,则在远大于设备安装频率的频段可忽略这种误差;若基座阻抗远大于机脚阻抗,则在设备无共振的频段亦可忽略这种误差.这些条件在工程中比较容易得到满足,因此本文结论对工程中导纳的测量具有实际指导意义.

Influence of Installed Machine upon Machine Mount Mobility Measurement

Mobility of bare machine mount is an important parameter in vibration isolation design. Therefore, it is necessary to measure mobility of the machine mount with installed machine in situ, which will lead to errors. Assuming that there is only one mounting point and this is right in low frequency band, it is verified theoretically by authors that these errors can be neglected in some cases. In the case of machine installed rigidly, machine mount impedance should be much bigger than machine impedance. In another case of machine installed resiliently, if machine mount impedance is much bigger than isolator impedance, the errors can be neglected in the frequency band which is much bigger than mounting frequency; if mount impedance is much bigger than machine impedance, the errors can be neglected in nonresonant frequency bands. Since it is easy to satisfy the foregoing conditions, the conclusions in this paper will conduct mobility measurement in engineering.