CADI磨球落球疲劳试验中的应力数值模拟及失效分析

摘要

应用大型有限元分析软件ANSYS/LS-DYNA对CADI磨球在落球疲劳试验单次落球过程中的应力场进行了数值模拟.结果表明:磨球碰撞接触界面剪应力峰值出现在略偏离接触界面中心位置,等效应力峰值出现在接触界面中心位置.残余等效应力峰值和残余剪应力峰值均出现在撞击部位周围挤压区.作者认为,是残余应力的累积、应力诱发马氏体相变和加工硬化、磨球材质及冶金质量等综合因素引起的材料疲劳损伤导致了磨球的表层剥落失效.磨球亚表层夹渣物的存在是造成剥落失效的直接原因.%In this paper, based on the finite element analysis software ANSYS/LS-DYNA, stress field of CADI grinding ball during the falling ball test with a single drop was simulated. The results show that the peak value of shear stress appears in the area slightly deviated from the center of the contact interface while the maximum of equivalent stress is just at the center of the contact interface. Both the peak of residual equivalent stress and residual shear stress appear in the neighboring extrusion zone of collision. It is believed that surface spalling failure of the CADI grinding ball is resulted from the fatigue damage of the material that caused by the accumulation of residual stress, stress-induced martensitic transformation, work hardening, material and metallurgical quality. The existence of slag in the subsurface of the ball is the real reason that causes the spalling failure of CADI ball.