Thermo-mechanical fatigue life prediction of heavy duty diesel engine cylinder heads

Due to the complex geometry and loading conditions, cylinder head is the most challenging part among all components in heavy duty diesel engines. It experiences both severe thermal loads and mechanical loads, resulting thermal fatigue, mechanical fatigue and thermo-mechanical fatigue (TMF). The demands for higher power and lower emissoins and fuel consumption accelerate fatigue. In this paper, a life time prediction process is presented with emphasis on analyses of multiaxial stress state and fatigue life assessment models in critical areas. The specimen test is used to obtain the material properties. The influences of thermal and mechanical loads on the critical areas are investigated. In addition, different fatigue life models are applied to estimate fatigue life of a heavy duty diesel engine cylinder head. It is proved that both the crack locations and life time are predicted with high accuracy.