A simplified approach for sheet forming processes design

Abstract

A new approach is developed to improve sheet forming parts and sheet forming processes design. In order to apply classical optimization methods, an energetic characterization of the global transformation of an elasto-plastic structure is proposed. After a brief review of thermostatics in elastoplastic laws, an energetic criterion is defined. With a geometrical definition of sheet forming processes, it is shown how to use this criterion to find the optimal displacement path between a flat blank and the part shape. Then, the classical assumptions of rigid-plastic behaviour and of thin shell geometry are introduced. Eventually, the criterion is used to define a formability criterion, for use at the preliminary design stage of parts. This paper concludes with numerical applications of the approach and analysis of formability criterion applications.