Setting Residual Stresses in Tensile Stress-Superposed Incremental Sheet Forming

Abstract

Incremental sheet metal sheet forming (ISF) is a flexible forming process to manufacture sheet metal parts. ISF processes allow a control of residual stresses depending on the process parameters and the acting forming mechanisms. These forming-induced residual stresses highly influence the product properties. This paper presents numerical and experimental results demonstrating the influence of biaxial tensile stress-superposed incremental forming (TSSIF) on the residual stress of truncated cones. An adjustable clamping frame is used to apply defined tensile stresses over the sheet plane in biaxial direction during forming. Residual stresses are evaluated by means of x-ray diffraction on both sides of the formed component. TSSIF influences the amplitudes of the residual stresses on both sides of the formed component. The residual stresses can be adjusted depending on the amount of initial tensile stresses in order to meet specified product properties.