基于热机耦合的气缸盖强度分析

Strength Analysis of Cylinder Head Based on Mechanical-thermal Coupled Method

气缸盖在工作过程中受载复杂,包括装配载荷、热载荷和爆压载荷。因此,在有限元分析中需要采用热机耦合的方法才能得到可靠的计算结果。针对耐久性试验中出现的缸盖开裂问题,采用热机耦合方法计算分析了缸盖的温度场、应力场和高周疲劳安全系数。计算结果表明,缸盖确实因存在疲劳安全系数不足而导致开裂。

Loads on the cylinder head are very complicated during engine operation, which include assembly load, thermal load and gas load. Hence, the acceptable results of finite element analysis should be obtained with mechanical-thermal coupled method. To cope with the crack problem of a cylinder head during the durability test, the mechanical-thermal coupled method was used to calculate the temperature field, the stress field and the high cycle fatigue safety factor of the cylinder head. The calculated results indicated that the cylinder head cracked due to the low fatigue safety factor.