Analysis and Simulation of Elastomeric Strut Mount and its applications for Failure Investigation

Abstract

This paper gives an insight of elastomeric strut mount and the complexities experienced by the rubber material. Running vehicles are exposed to almost constant vibration excitation; shock absorbers are constantly required for reasons of driving safety and riding comfort. Strut is basically a shock absorber mounted inside a coil spring. Macpherson strut suspension consists of top rubber mount which helps in isolation of road vibrations and noise from entering passenger compartment. Poor design can cause excessive vibration and noise problem. Stress analysis of rubber components is often demanding on account of difficulties posed by complex behavior of rubber. When it comes to fatigue predictions of rubber components, this complexity increases multifold. Further, in time bound development projects, it becomes very difficult to dedicate sufficient time to tests and gather data required to characterize rubber accurately. In such cases, more practical approach is to make design improvements through simulations based on approximate rubber models followed by validation through physical tests. Hyperelastic material models (Yeoh, Mooney-Rivlin) for rubber in strut mounts are compared using uniaxial test data. Yeoh model with 5 parameters provides accurate stress-strain prediction for FEA. By acquiring the stress concentration on the existing piece of natural rubber and the top mount, further changes in design need to be done. It is yet to be seen how rubber behaves after a force acts on it.