Identification of damping ratio of vibration system with large damping

(Adaptation of half-power method for small-damped frequency response function)

Abstract

It is important to identify modal damping ratios of natural vibrations for reduction of structural vibrations. Experimental modal analysis has been proposed to identified modal damping ratio. Half-power method is one of identification methods of the modal damping ratio. This method is commonly used to identify damping ratio; however, it is known that identification accuracy of damping ratio is low when the damping ratio is high. In this paper, the novel identification method of the damping ratio for the vibration system with large damping by half-power method using small-damped control is proposed. First, the theory of half-power-method and the overview of half-power method using small-damped control are explained. Second, the theory of identification method by half-power method using small-damped control and the measurement method of small-damped frequency response function are. Finally, the experimental investigation using single-degree-of-freedom system is conducted. The improvement of identification accuracy of damping ratio using proposed method is realized.