A Study on Vehicle Elastomer Mount Preloading and Impact Response with Test Validation 2005-01-1415
A variety of elastomer mounts are being used for vehicles as isolators/dampers between body and frame, on the engine cradle, etc. These vehicle flexible mounts, made of mainly rubber materials and housed in a metallic tube, are indispensable components affecting the quality of the vehicle ride, noise and vibration. In the auto industry, the usual practice when designing vehicle flexible mounts is to minimally reflect impact considerations in the mount design features. However, in most high-speed vehicle crash events where the mounts fail, the crash responses, including occupant injury severity, are known to be very different from the responses of non-failure cases. Even in low-speed vehicle impact cases, excessive deformation of the flexible mounts could cause significant variance in the compliance of the vehicle acceleration level to the air-bag firing and timing threshold requirements. Therefore, flexibility and failure of the flexible mounts need to be accurately evaluated for their crash responses, and fully considered for their effects on the full vehicle impact responses, as well as for subsequent decisions on impact performance improvement direction. This paper, with a view to identify the impact characteristics of the elastomer mounts, 1) developed a FE(Finite Element) representation of a detailed vehicle rubber mount model coupled with failure criteria and initial bolt wrenching (preloading) using a FE tool, 2) investigated the expected impact behavior and failing process of the elastomer mount, and 3) validated the FE model with a variety of tests.