Simulation Analysis on the Failure Mechanism of Cylinder Head Based on Test Load Spectra

In view of the problem that the run-through fracture between the water jacket and intake port wall of the aluminum cylinder head in a highly intensified diesel engine happens several times in bench tests, finite element software Abaqus is used to analyze the temperature field and thermo-mechanical coupled stress field in the failure regions of cylinder head and their time-varying rule based on test load spectra, and fatigue life prediction theory is applied to the comparative analysis on the main factors affecting fatigue life of that type of cylinder head. The results show that too large an injector tightening torque and the high dispersiveness of casting residual stress are the radical causes of the fracture between the water jacket and intake port wall of that type of cylinder head, and reasonably reducing the injector tightening torque and controling the casting residual stress in the failure regions of cylinder head will significantly enhance the durability of that type of cylinder head.