Analysis Study Of Automotive Exhaust System Fatigue Durability

With the rapid development of China's automobile industry, the performance of the components on the car growing concern, Among them, the fatigue durability is an important aspect of the performance of the components. Exhaust system, as an essential components of a car, its fatigue life issues have gradually become the focus of attention. In view of the less study of exhaust system in this respect less domestic, and the great gap between the level of research over the same period abroad, so it's necessary to strengthen research in the field to make up deficiencies in short term, research results obtained in the analysis will add a certain extent to this field, and it can be the references of the overall modeling of the exhaust system of Fatigue durability analysis.In this paper, based on research results of the CAE analysis technology field of automobile exhaust system fatigue durability domestic and foreign, completed the finite element meshing and modeling of a vehicle exhaust system in Hypermesh version 8.0, and finished computational modal analysis of the finite model in Nastran, while leveraging LMS test instrumentation system to complete experimental modal analysis of the entity, both reference to General Motors standard GMW14202:Exhaust System Modal Analysis Evaluation Procedure, and then compare the two results in order to test the model confidence, confidence can qualify for the follow-up calculation model.Based on the high accuracy model after modal confidence test, established a finite element stress analysis model in hypermesh version 8.0, and obtained the stress analysis results from stress analysis after applied load on the exhaust system model. Then imported the results into MSC.Fatigue, and completed the fatigue life analysis of the exhaust system using Palmgren-Miner cumulative damage theory after set material S-N curve and post-load characteristics.As the fatigue analysis results shows that the exhaust system don't meet design requirements, it is necessary to improve the exhaust system. Choosing improving methods are completed after discussion, first, change stiffness of flex decoupler, and then adjust the position of hangers. After analysis of the modified model in accordance with fatigue analysis process, the results show improvements works well, has basically reached the design requirements, indicating that the method works well, and the mothod can used to try to guide the resolution of engineering problems.Keywords:Automotive Exhaust System; Fatigue Durability Analysis; Improved Design...