Numerical model for a quantitative estimation of sliver formation in shearing process

In the present research work a model for the estimation of the probability of sliver formation during the shearing process, based on the amount of damage in the element adjacent to the shearing edge, is proposed. A full material characterization, considering different temperatures and strain rates, have been carried out in order to determine the model constants for Johnson-Cook (JC) flow stress and damage model. A 3D numerical simulation replicating the shearing process has been implemented in ABAQUS/Explicit and the results of the shearing surface have been compared with those of laboratory experiments, proving the validity of the developed simulation. Finally, while varying holder force, clearance and punch velocity, the average damage in the elements adjacent to the shearing edge have been calculated and the results allowed to conclude that punch velocity has the higher influence on the damage in the shearing edge but also that holder force and clearance percentage cannot be neglected. A too high punch velocity, as well as a higher holder force, result in an increase of the damage state, whereas a higher clearance percentage allows reducing it. Based on the proposed correlation between damage in the burrs and probability of sliver formation, the combination of process parameters those assure to reduce the probability of sliver occurrence can be identified.