Comparison of the Ductile and FLD Damage Criteria in Prediction of Damage Evolution in Tandem Cold Rolling

Continuum damage mechanics is a powerful tool for predicting mechanical defects in the final products of metal forming processes، including tandem cold rolling. Generally speaking، there are various criteria to predict damage evolution in different processes. In the present study، the ductile damage model and the FLD criterion، as two widely used damage models، are employed and compared in order to predict strip tearing in tandem cold rolling process. Strip tearing is one of the manufacturing issues which can considerably raise the production costs. Therefore، it is necessary to develop an effective numerical model to predict strip tearing and analyze the effective factors which are related to this phenomenon. In this work، an industrial five-stand cold rolling mill is simulated using ABAQUS/Explicit finite element code. The ductile and FLD damage criteria are implemented and utilized to predict damage evolution through the strip. The damage parameters of material are determined from experiments. By comparison of numerical results with experimental observations، the more accurate and efficient damage model is selected and introduced. Finally the effect of the variations of angular velocity of the work rolls on damage evolution is investigated by applying the introduced damage model.