FEA Based Dynamic Vibration Response Analysis of Loose Mounted Heavy Vehicle Transmission Gearbox Casing

Abstract

The main objective of this research work is to study the dynamic vibration characteristics of loose transmission gearbox casing. The loose vehicle transmission casing produces heavy vibration and noise. Noise and vibrations are the two technical indexes for the transmission failure. Truck transmission gearbox assembly is subjected to harmonic and meshing excitation. These excitation forces are the main reason of noise and vibration. The vehicle gearbox casing is mounted on chassis frame using connecting bolts fixture. 37 positional connecting bolts fixture were used to constraint the casing on chassis frame. This study is carried out in three stages. In first stage zero displacement constraint based boundary condition were used to evaluate the exact natural frequency and mode shapes. In second stage 4 fixture bolts were loosened, natural frequency and mode shapes were evaluated. In third stage all bolts of left positional view is unconstrained, natural frequency and mode shapes were evaluated. Reciprocity Principle was used to apply the loads on casing. The first 10 vibration mode shapes and natural frequencies were calculated using ANSYS 14.5. The study has practical importance for the structure optimization of gearbox casing. ANSYS 14.5 is used as FEA based analysis tool. The natural frequency for zero displacement condition varies from 1669 Hz to 2865 Hz. The simulation results were verified with experimental result available in literature.