仪器—基础耦合振动固有频率偏移

Natural frequencies distribution of instrument-base dynamic coupled system

针对柔性基础上精密仪器的隔振设计问题,对仪器-基础耦合振动刚度矩阵进行了求解。对耦合系统的固有频率偏移进行了数值计算。研究表明:耦合系统基频小于仪器的安装频率。在低频段,仪器纵向振动刚体模态与基础第1阶弯曲模态动力耦合效应明显。

The stiffness matrix of a rigid instrument and a flexible foundation dynamic coupled system was derived in vibration mode space. The natural frequencies distribution of the coupled system was studied numerically. The numerical results show that the first frequency of the coupled system is commonly lower than the instrument's mounting frequency. In the low frequency band, the instrument's bounce mode is coupled with the flexible foundation's first bending mode distinctly. In the high frequency band, the flexible foundation's mode is the dominant mode of the coupled system. The model studied in this paper can be considered as an on-board precision instrument vibration isolation model.