发动机缸体主轴承座裂解槽裂尖应力应变场研究

Research on stress-strain field of fracture splitting notch crack tip of engine cylinder's main bearing wall

裂解槽是裂解加工的初始裂解源,裂尖的应力应变场直接影响着剖分类零件的断裂特性,是裂解加工的关键参数。本文以某汽车发动机缸体为研究对象,用解理断裂正应力判据作为理论基础,利用断裂力学软件ABAQUS模拟分析不同裂解槽参数下断裂前裂尖附近的应力应变场。分析结果表明:缸体材料QT500常温呈脆性,缺口不敏感;综合考虑裂纹形核、扩展、裂解槽加工及裂解载荷等问题,确定缸体主轴承座裂解槽的最优参数值。经实验验证,该裂解槽参数获得很好的裂解效果。

Fracture splitting notch is the initial fracture source of fracture splitting process,and stress-strain field of crank tip directly affects the fracture characteristics of subdivision parts,which makes it become the key parameters of this process.Normal stress criterion of cleavage fracture was taken as theoretical foundation,and the stress-strain field of crank tip was simulated and analyzed,with software ABAQUS and different parameters of fracture splitting notch.The results show that material of cylinder QT500 appears brittle at normal temperature,and the notch is insensitive.Considering the crack nucleation,extension,machining of fracture splitting notch,fracture splitting load and other problems,the optimum parameters are determined,tested and verified to have good performance.