A New Technique for Hanger Position Optimization of Vehicle Exhaust System

A simulation technique using a finite element method (FEM) model for predicting, reducing and optimizing vibrations of the exhaust system was developed in this paper. Based on a sample vehicle, the HyperMesh and MSC. Nastran software are adopted for meshing and calculation in the FEM modeling and vibration modal analysis of the exhaust system. In view of the reduction of the exhaust vibration effect on the whole vehicle, according to the simulated results, a method called averaged driving DOF displacement (ADDOFD), is used to determine and optimize the exhaust hanger positions. Furthermore, The determined hanger positions are proved by the calculated node acceleration spectra from both the frequency-response analysis (FRA) and the random-response analysis (RRA) of the exhaust system. The results suggest that, in the pre-development stages of a vehicle design, the HyperMesh, MSC. Nastran software and the ADDOFD method are effective and feasible for simulation and hanger position assignment of the vehicle exhaust system. The work done in this paper can be extended to other types of vehicle, thus, is instructive for saving both the time and the cost in the development of new vehicles.