发动机缸体线性与非线性对比分析

采用线性分析发动机缸体时,在螺栓接触和绑定的位置会出现明显的应力集中点,且计算得到疲劳安全因数远远低于合理值.在考虑材料非线性的基础上对发动机缸体进行非线性分析,发现在螺栓接触和绑定位置处的应力明显降低,计算得到的疲劳安全因数也趋于合理.通过汽油机缸体线性与非线性对比分析可以发现,缸体非线性模型的计算结果更合理.若要改善螺栓孔周边的安全因数,一定要保证螺栓绑定和接触位置接近实际情况,特别在2个面过渡的位置不能绑定,这样可以避免造成应力集中.

Comparison of linear and nonlinear analysis on engine block

The block of engine is analyzed by linear model. The stress concentration occurs on the edge of nut or thread tied with the bolt hole and the minimum safety factor is lower than the reasonable value. When the plastic properties of block material is considered, the stress lied on the location of bolt hole decreases significantly, at the same time the minimum fatigue factor becomes reasonable. Through the comparison analysis between the linear and nonlinear models of block for gasoline engine, it is believed that the non linear model should be chosen. When the tied place of bolt is close to the actual and the transition of two faces are not tied, the stress concentration could be avoided and the minimum safety factor could also be improved.