The Thermal-mechanical Strength And Fatigue Simulation Analysis Of The Cylinder Cover In Marine Two Stroke Diesel Engine

As an important part of combustion chamber, the stress that cylinder cover bears is very complex, it bears gas explosion pressure and bolt pre-tightening force at the same time. Besides, because of directing contact with high temperature gas and cooling liquid on both sides, cylinder cover bears thermal stress generated by temperature difference. Due to dynamic load of explosion pressure, each node of cylinder cover occurs periodic oscillating. So it’s prone to fatigue. In addition, inevitably, there are areas that can cause abrupt change of cross-section exist in the cylinder cover. These areas are prone to thermal stress or mechanical stress concentration. As an important part of diesel engine, the cylinder cover’ strength has significant impact on the reliability of diesel engine, so strength analysis on cylinder cover is particularly necessary.In view of the complexity of cylinder cover’s structure, this paper uses Pro/Engineer to establish its three-dimensional geometric model, then, use HyperMesh to mesh it. This paper introduces the model into ANSYS, and analyzes the strength of cylinder cover after reasonably determine load and constraint conditions. At last this paper analyzes the cylinder cover’s fatigue in FE-SAFE, basing on the final analysis of ANSYS.The results reveal that thermal stress is much higher than mechanical stress, and it is batter to restrict thermal stress to improve the bearing capacity of the cylinder cover. Both the worst strength and fatigue area of cylinder cover appear in the stress concentration part, so it is very important to improve the component’s life by improving the phenomenon of stress concentration.Based on the strength and life analysis of cylinder cover, this paper lays the foundation for improve structure optimization, reasonable stress and reliability, and provides a basis for design and management of diesel engine.