Vibration analysis of APS magnet/support systems based on the finite element method

摘要

Prediction of the dynamic response of APS magnet/support systems requires knowledge of the free vibrational characteristics, including natural frequencies, modes, and modal damping ratios. A preliminary dynamic analysis of the magnet/support system of a typical section of the APS storage ring, as presented in the APS Conceptual Design Report, was performed to gain insight. The preliminary analysis is based on the assumption that the support girder could be considered rigid relative to the stiffness of the pedestal supports when considering the lower modes and frequencies. Further, only the vertical (in-plane) translational and rocking modes were studied. The subject analysis was performed to include the flexibility of the support girder and to investigate the horizontal (out-of-plane) modes as well. Also, the most up-to-date design of the five magnet sections are studied. Here, it should be noted that in the latest design the positioning of the support pedestals (jack-screws) is different from that in the conceptual design.