A study on AGV-induced floor micro-vibration in TFT-LCD high-technology fabs

Abstract

This study explores vertical floor micro-vibration induced by the automated guided vehicles (AGVs) in thin-film-transistor liquid-crystal-display (TFT-LCD) fabs. The state-space procedure is adopted to compute the AGV-induced floor vibration as it preserves the desired numerical stability and accuracy in high-frequency responses. The dynamic analysis of an AGV moving on an equivalent three-span beam model of a TFT-LCD building is simulated by taking into account various AGV speeds and engine forces. Numerical simulations demonstrate that if proper engine forces and excitation frequency contents of the AGV moving loads are used, the peak AGV-induced floor micro-vibration level can be predicted by the proposed method. Moreover, the effectiveness of vibration control by span-reduction as well as energy-dissipation by viscoelastic dampers is also examined. In comparison with span-reduction, application of energy-dissipation devices is more effective in vibration suppression as they enhance the damping characteristics of the multi-span floor system whose natural frequencies are potentially in resonance with the excitation frequencies of the AGV moving loads ranging in a broad bandwidth. Copyright © 2011 John Wiley & Sons, Ltd.