Influence of material properties on the interaction between residual stress and springback in the case of in plane sheets forming

In the case of cold forming of sheets metal, the springback phenomenon leads to undesired effects on the geometry and dimensions of the formed parts. One of the main causes that lead and influence the intensity of this instability phenomenon is the state of stresses generated by the forming process in the deformed material. To establish an interaction between springback and distribution of stresses it must be known the law of variation of their parameters, their factors of influence and their causes. If the determination of springback parameters can be performed without difficulty, the determination of stresses variation in the case of out of plane sheet metal forming is a difficult problem because of the complexity of process, tools and part geometry. A solution of the problem can be the determination of stresses and of their interaction with springback in the case of in plane forming, the obtained model of interaction following to be extended for the case of out of plane forming of metal sheets. The present paper performs an analysis of the influence of materials on the interaction between the state of stresses generated by tensile loading and springback in the case of in plane forming by applying the principles of the three bars method.