Evaluation of frequency dependent rubber mount stiffness and damping by impact test

A simple experimental method is presented in this paper to evaluate the frequency dependent rubber mount stiffness and damping characteristics by utilizing the measured complex frequency response function from impact test and by least-squares polynomial curve fitting the data obtained from the test. The study shows the transition of the rubber mount stiffness from static to dynamic values. Using the experimentally estimated values of the rubber mount stiffness and damping, the dynamic response of the tested spring-mass system using a rubber mount as the elastic element can be accurately reproduced. In contrast, it is found that the single degree of freedom ideal spring-mass model using constant stiffness and damping values can only predict the response of the system accurately at resonance but not at non-resonance frequencies. The proposed method is validated by comparing its results with those obtained by using mechanical shaker excitations and those of conventional direct stiffness method using blocked transfer frequency response functions.