Mitigation of micro vibration by viscous dampers

Abstract

This study proposes a micro vibration mitigation system using viscous dampers to solve the problem of vibration in a high-tech building. Due to the operating frequency of the air conditioners and fundamental mode of the fl oors, a resonant phenomenon is occasionally experienced at the upper levels of the structure. Several strategies were considered, and viscous dampers combined with a suspension system were chosen to mitigate this annoying situation. A theoretical analysis was fi rst executed to determine the optimal design value of the damper and the suspension spring. An effi cient reduction in fl oor velocity of approximately 50 % was achieved by the proposed system. Practical verifi cations including a performance test of the micro-vibration-oriented dampers, the pragmatic application result, and a comparison in one-third octave spectrum was then carried out. The performance of the system was demonstrated by the data measured. It alleviated more trembling than was numerically expected. The energy absorbed by the viscous dampers is illustrated by the hysteresis loops and the one-third octave spectrum. It is found that with the proposed system, the vibration can be effectively captured by the viscous damper and converted to lower frequency-content tremors. The success of this project greatly supports the proposed standard two-stage analysis procedure for mitigating micro-vibration problems in practice. This research extends the use of viscous dampers to a new fi eld.

Experimental study on seismic vibration control of stockers in wafer and LCD panel fabs

“…For example, Asfar and Akour [9] presented a numerical study for the suppression of self-excited oscillator using an impact viscous damper. Lin et al [10] proposed a micro vibration mitigation system using viscous dampers to reduce the vibration in a high-tech building. Hong et.…”

Investigation of vibration induced by moving cranes in high-tech factories

“…[16][17][18][19][20][21][22][23] Hwang et al 16 studied the seismic protective systems for high-tech structures, and found that the incorporation of viscous dampers not only enhance the seismic safety but also minimize the micro-vibration of the structure. Lin et al 17 proposed a micro vibration mitigation system using viscous dampers for high-tech buildings, and results presented that the vibration can be effectively captured by the viscous damper and converted to lower frequencycontent tremors. Shih et al 18 studied the effect of different damper for high-tech buildings, and found the Velocity and Displacement Hydraulic Damper has superior vibration-reduction capability in reducing vibration.…”

“…A number of studies used isolators or dampers to reduce vibration for high-tech buildings. 16–23 Hwang et al. 16 studied the seismic protective systems for high-tech structures, and found that the incorporation of viscous dampers not only enhance the seismic safety but also minimize the micro-vibration of the structure.…”

“…Lin et al. 17 proposed a micro vibration mitigation system using viscous dampers for high-tech buildings, and results presented that the vibration can be effectively captured by the viscous damper and converted to lower frequency-content tremors. Shih et al.…”

Investigation on Spectral Aliasing Error Resulted from Truncating Signals Incoherently

“…The other one is to correct the DFT spectrum directly in frequency domain. Existing spectrum correction methods [7][8][9] use the main spectral line and some near the main one of DFT to get higher accuracy parameters of the signal. However, the accuracy of these correct methods is limited for the used spectral lines containing the truncation aliasing error.…”