Fatigue durability of a vehicle exhaust system analysis

With the rapid development of China's automobile industry, the performance of the various components of the vehicle increasing concern, in which parts of the fatigue durability is an important part of the performance. Exhaust system, as an indispensable vehicle parts, it's fatigue life issue has become the focus of attention. In view of the exhaust system of the domestic research in this area less gap between the level of research with foreign countries over the same period were so great that the need to strengthen research in the field, so as to make up for deficiencies in this area of China, the research results obtained in this field will be a certain degree of complement, can be used as the fatigue durability of the exhaust system, the overall modeling reference. In this paper, the fatigue durability of automotive exhaust systems at home and abroad CAE analysis technology related research, based on finite element analysis, completed in Hypermesh 8.0 in the vehicle exhaust system of a finite element meshing and modeling, and General Motors GMW14202 reference evaluation and analysis process exhaust system, built using NASTRAN finite element model of the calculated modal analysis, and test equipment using LMS system to complete the physical experimental modal analysis, and analysis of the results of the two to test the model comparison confidence, confidence can qualified for subsequent calculation model. Confidence test based on modal high accuracy after the model established in Hypermesh 8.0 in the finite element analysis model of the exhaust system model of the model after the completion of the applied load stress analysis, obtained the results of stress analysis of the exhaust system . Then the result into MSC.Fatigue, complete material SN curve and load characteristics of the set, using Palmgren-Miner cumulative damage theory completed the fatigue life of the exhaust system. Due to fatigue analysis showed that did not meet the design requirements, it is necessary to improve the exhaust system.Improved methods to complete the discussion and choice, select the first changes in bellows stiffness, and then adjust the position of the hook method. In accordance with the fatigue analysis of a modified model is analyzed, the results show that the improved result is good, has basically reached the design requirements, indicating that the method is effective, try to guide to solve practical engineering problems. 

 

Keywords automotive exhaust systems; fatigue durability analysis; improved design