Dynamic stiffness and loss factor measurement of engine rubber mount by impact test

Abstract

Dynamic stiffness and loss factor for engine rubber mount are important dynamic behaviours to represent the performance of an engine mount system. The investigation of the dynamic behaviour of engine mount system using impact technique, particularly in the simultaneous measurement of the dynamic transfer stiffness and driving point stiffness where the impact hammer replaces the shaker as the source of excitation is presented in this paper. The results showed that the dynamic driving point stiffness can only be used to represent the dynamic transfer stiffness for the lower range of frequency. The curve fitted functions of the loss factor obtained from the dynamic driving point stiffness measurement showed linear dependency on the frequency and the loss factor obtained from the transfer stiffness measurement showed non-linear dependency on the frequency. Both of the stiffnesses are accurately reproduced by using these functions. The values of both dynamic stiffnesses obtained from impact technique are validated with the values obtained from shaker.