Numerical modeling of damage accumulation mechanism in ball burnishing with undefined ball motion of AA6061-T6

In burnishing process, due to local deformation and ball rolling, material is subjected to complex stress state and different stress components are applied to the workpiece. Under these loading conditions, material enters the plastic zone and accumulation of plastic strain leads to the development of damage within the workpiece. Damage prediction in multi-stage processes is challenging. In this work, modeling of process was performed using finite element (FE) method and contact mechanics theory. Little research has been done on the mechanism of damage accumulation in burnishing, so the aim of this work is to investigate the process mechanics and damage prediction using a nonlinear model. The damage model was defined by the VUSDFLD subroutine in Abaqus software. The effect of reverse loading on damage growth and the accuracy of predicting failure onset was investigated. Deformation mechanics indicate severe changes in the stress state, which should be considered in the calibration of damage criterion. Therefore, the nonlinear model was calibrated by a new test appropriate to the loading in burnishing. According to the results, using the nonlinear criterion and choosing the damage formation threshold of − 2 3 , the critical penetration depth was predicted with an error of 4.54 %. The effect of threshold value on the moment and location of failure initiation is significant, such that its non-definition led to an error of 36.4 % in predicting the critical penetration depth. Plastic strain was used to estimate the work hardening. The variations in plastic strain along the thickness correspond to hardness distribution in workpiece.