发动机排气门热-机械耦合应力数值分析

Numerical Analysis of Thermal-Mechanical-Coupled Stress of Engine Exhaust Valve

建立了某发动机排气门组有限元耦合模型,模拟了排气门在热-机械负荷共同作用下的耦合应力场分布规律。计算结果表明:气门锥面处周期性变化的应力是导致气门锥面疲劳点蚀的主要原因;气门锁夹槽处的应力变化会导致气门锁夹槽疲劳断裂。这为排气门材料的选择提供了参考,为气门进一步结构设计和优化设计奠定基础;气门的热膨胀量为气门间隙的设置提供依据;同时,三维有限元法能为内燃机零部件的进一步设计改进提供了很好的理论依据。

A transient thermal coupling model of certain internal combustion engine exhaust valve train was built,transient stressfield distribution of the exhaust valve subjected to thermal load and mechanical load were simulated.The calculation results show that the stress of the valve cone changes periodically,which is the main reason of the valve cone pit corrosion;the changes of stress of the sandwich groove of valve lock lead to its fatigue failure.These provide reference for the choice of materials of the exhaust valve and lay foundation of the further structural design and optimization of the valve.The thermal expansion of valve provides the basis for the valve clearance setting;at the same time,3-D FEM provides a good theoretical basis in the process of the design and improvement for the parts of ICE.