In a passenger car, suspension link bushings, engine and transmission mount bushings and bump-stops are made of elastomeric materials, to maximize the durability and comfort. Thus, deformation behavior of rubber and its durability is important for product design and development. In virtual engineering, simulating rubber fatigue is a complex exercise, since it needs right modeling strategy and coupon based testing material data. Principal stretches based Ogden model is used to characterize the hyper elastic deformation behavior of natural rubber. Fatigue crack growth approach used here for the fatigue analysis.
Engine torque strut mount is used to control the engine and transmission fore aft motion and it is connected between body and Powertrain (PT) system. Powertrain events are predominant for damage contribution to mount failure. So, it is important to predict fatigue life of mount elastomer bushing under Powertrain loading.
The objective of this work is CAE fatigue life prediction correlation with bench test for the elastomeric bushing for PT schedule loads. Virtual static simulation was carried out for PT block cycle load to find deformation mode and then material cracking energy density (CED) parameter were used to predict the fatigue life. The estimated fatigue life was correlated well with physical test results on a conservative side. The conservative prediction versus bench test results assures that the used tool is capable for CAE purposes. Based on the correlation study, this approach can be used for other rubber bushing/mount designs.