Prediction of strength of drawn bar considering non-uniform strain distribution

In bar drawing process, the material passes through the drawing die. The surface of the material directly in contact with the drawing die has a relatively higher strain and strain rate than the center. That is, a non-uniform strain distribution appears over the cross-section of the drawn material, such that it is concentrated on the surface of the material and relatively low at the center, thus, residual stress or wire breakage may occur in the drawn material. The purpose of this study is to predict the non-uniform strain distribution from the center to the surface of a drawn bar and apply this prediction to evaluate its strength. In this study, the strain distribution was evaluated using finite element analysis and a non-uniform strain prediction model. Then, a strength prediction model considering the non-uniform strain distribution was proposed. Finally, the strain and strength prediction models were experimentally verified through a multistage drawing experiment.