抄録
Shake tables are used for studying the effects of vibration or evaluating the physical properties of materials or structures. In this paper, cross-talk phenomenon in a two-axis electro-dynamic shake table utilizing hydrostatic oil bearings is examined by both experimental and multi-body dynamics (MBD) approaches. Once cross-talk begins, the performance of the shake table significantly degrades. In this investigation of cross-talk phenomena, first, experiments were conducted and then simulation analyses were carried out. The authors improvised and approximated an oil bearing element to use with a general purpose MBD software. This paper describes the modeling of the oil bearing, the mechanical system and the electrical system. The results of experimental studies using an actual shake table and computer simulations were compared. Acceleration responses are in fairly good agreement under specific conditions. Mechanisms of the cross-talk were partly elucidated in terms of natural frequencies and mode shapes with respect to the change of the vertical location of the horizontally directed actuating force or the change of the oil film thickness. These studies also proved the usefulness of using MBD for analyzing the coupled mechanical and electrical systems. Due to the lack of a hydrostatic oil bearing element in RecurDyn at the time of this study, the authors employed nonlinear springs to simulate the hydrostatic behavior of the oil bearings.
