A recommendation of computation of normal stresses in single point incremental forming technology

Abstract

Single Point Incremental Forming (SPIF) has become popular for metal sheet forming technology in industry in many advanced countries. In the recent decade, there were lots of related studies that have concentrated on this new technology by Finite Element Method as well as by empirical practice. There have had very rare studies by pure analytical theory and almost all these researches were based on the formula of ISEKI. However, we consider that this formula does not reflect yet t,he mechanics of destruction of the sheet work piece as well as the behavior of the sheet in reality. The main aim of this paper is to examine this formula and to suggest a new analytical computation of three elements of stresses at any random point on the sheet work piece. The suggested formula is carefully verified by the results of Finite Element Method simulation as well as by empirical evidence. Absolute hardness of the forming tool and homogeneous and isotropic material are supposed in this paper.