Influence of Rubber Temperature on Transfer Functions of Bushings 2015-01-9115

In ride comfort as well as driving dynamics, the behavior of the vehicle is affected by several subsystems and their properties. When analyzing the suspension, especially the characteristics of the main spring and damper but also rubber bushings are of main importance. Still, the properties of the different components are dependent on the present operating conditions. Concerning rubber bushings, several effects have already been investigated, e.g. dependencies of the transfer function of frequency, amplitude or load history. In this context influences of changes in temperature are often neglected. However, in the following research, the focus specifically lies on determination and analysis of the temperature dependency of rubber bushings. For this purpose, initially the relationship between properties of pure rubber and rubber bushings is described, which serves as a basis for correlating respective temperature dependencies. Furthermore, bushings of the suspension and power train have been measured using a novel testing method for vehicle bushings incorporating a hydraulic test rig in combination with a heating chamber. Based on the conducted measurements, static as well as dynamic properties of the bushings are presented. In this context, the results are analyzed using the previously presented material properties as well as structural and geometrical aspects of the respective bushing. An outlook on the influence on full vehicle characteristics is given. Based on the presented findings, simulation models of rubber bushings as well as determination of component, subsystem, and full vehicle properties can be improved when temperature dependency is considered.