Calculation of Fatigue Life of Rubber Vibration Isolators Under Random Vibration Loads

In order to effectively calculate the fatigue life of rubber vibration isolator under random vibration loads, a rubber vibration isolator for air conditioning compressor of an electric vehicle was taken as the research object, and the road spectrum acquisition of rubber vibration isolator was carried out, by which the acceleration signals versus time of rubber vibration isolator were obtained. Then, Fourier transform was used to transform the acceleration signals into the acceleration power spectral density as load input, and a random vibration test of rubber vibration isolator for compressor was carried out under variable temperature and constant humidity conditions, with the cracking of main spring of rubber vibration isolator being observed. Moreover, a finite element model of rubber vibration isolator was established, with its validity being verified by static characteristic tests as the relative error between simulation value and test value is within ±5%. In addition, frequency response of rubber vibration isolator under unit load was analyzed by ABAQUS, that is, extracting and importing stress response PSD of rubber element into Fe-safe, and using acceleration PSD as load input to calculate the fatigue life. The calculated results were compared with the random vibration test results, finding that the predicted life is consistent with test data, with a relative error of only 2. 5%, and that fatigue danger position of rubber vibration isolator unit can be effectively predicted. Finally, the structure of rubber vibration isolator was improved, through which the fatigue life of rubber vibration isolator is 2. 8 times that before the improvement, meaning that the fatigue life design requirements are successfully met. This study helps to shorten the design cycle of rubber vibration isolator and reduce the cost of sample test.