Effect of the Thermal Mean Stress Value on the Vibration Fatigue Assessment of the Exhaust System of a Motorcycle Engine

The exhaust manifold of a high-performance motorcycle engine is subjected to combined thermal
and vibrational loadings. In this research, the whole fatigue assessment of an exhaust manifold is
addressed. First, a classic low-cycle fatigue analysis is performed. Then, a specific methodology for
determining the fatigue cycle of components subjected to thermal and vibration loadings is developed
and presented in a way that possible damages can be evaluated. The results are post-processed
and the damage caused by fatigue cycles is computed referring to the Wöhler curve of the material
using the Dirlik approach.