THE VIBRATION ANALYSIS OF AUTOMOBILE OUTER REAR VIEW MIRROR WITH ITS DEVELOPMENT AND OPTIMIZATION

Abstract

The external and internal mirrors used particularly in high mass recreational and commercial vehicles are prone to vibrations. Effect of undesired vibrations in the mirror assembly like blurring of image, breaking of the mirror glass, breaking of plastic mounting bracket due to resonance is a major challenge and requires vibration analysis based studies during the development stage of the mirror assembly. The purpose of this study was to carry out vibration analysis on a basic pre-existing mirror assembly from an OEM (original equipment manufacturer) and further develop this assembly to increase its first fundamental frequency above the target specified by the OEM. Finite element model for the automobile rear view mirror was created to predict mirror vibration response based on modal analysis study. The design changes in various parts of mirror assembly were done in solid works and the Hypermesh 9.0 was used to prepare the FEA model. The materials used in this FEA model were initially provided by the mirror manufacturer and also some modification was done based on the study. Hypermesh Optistruct solver was used to build the complete FEA ORVM model. Vibration modes were predicted for the mirror assembly with a special focus on the mirror mounting bracket as it’s the only part through which the vibrations transfers to mirror assembly in actual vehicle. The natural frequency of the first mirror FEA model was correlated with the first test results and then further iterations were done using this FEA model to predict the changes required in material and geometry to achieve the target frequency value.