Sloshing characteristics of annular tuned liquid damper (ATLD) for applications in composite bushings

It is of great significance to conduct seismic qualification and mitigation for composite bushing, whose damage may cause massive power outage and huge cost of repair. In this paper, the annular tuned liquid damper (ATLD), utilizing the sloshing characteristics of transformer oil in the dome, is proposed to reduce the seismic responses of the composite bushing. As to the annular feature of the metallic dome, the simplified formulas for calculating the liquid sloshing frequencies in the dome are derived based on the linear wave theory, which provides a direct and fast way for the predesign of ATLD. Comparing with the experimental results reported in literature, the accuracy and applicability of the proposed formulas are verified. In addition, parametric studies of the first 3 sloshing frequencies including liquid height and the outer and the inner radii are carried out. The optimal tuning analysis of vibration reduction in frequency domain is performed on the structure base excitation. The vibration reduction analyses in time domain of the ATLD for the composite bushing subjected to real earthquake records are carried out and discussed simultaneously. It is shown that the simplified formulas presented in this paper provide a convenience for the predesign of ATLD and the optimal ATLD is effective in reducing the vibration of the composite bushing.