Prediction of Fatigue Strength of Motorcycle Exhaust System in Higher Temperature Range 2022-32-0011

When developing a motorcycle exhaust system, it is important to predict the fatigue durability of the exhaust system during the design stage. We have been predicting fatigue durability using our own methods [1]. In recent years, however, in order to meet stricter emission regulations, the installation position of a catalyzer has been changed and the temperature of the exhaust system has been increased. Accordingly, the required fatigue durability of mufflers is at higher temperatures than before. With such a change in situation, a prediction method with higher accuracy for fatigue durability that can handle a higher temperature range, was required. The exhaust system temperature distribution and the physical properties of the material change depending on the temperature. Therefore, in the simulation model developed this time, the temperature distribution of the exhaust system is calculated by a heat conduction analysis method applying FEM. Furthermore, based on the temperature distribution, the values of the material properties are set for each element. In order to verify the effectiveness of the constructed model, measurements were performed on a real motorcycle. In the measurement on an actual vehicle in this study, a glass bonding method was developed and adopted for the purpose of bonding the optical fiber strain gauge. The results yielded by using the fatigue durability prediction method, constructed in this study, were in agreement with the results of the actual vehicular tests, confirming the effectiveness of this analysis method.