engleski

Modification of initial blank shape for earing minimization in cylindrical cup deep drawing of EDD steel sheet

Sheet metals demonstrate a certain initial plastic anisotropy mainly due to the crystallographic texture caused by production rolling steps. In cylindrical cup deep drawing process, in which a cup is drawn from a blank sheet, anisotropic plastic material behavior results in formation of wavy edge on the top of the drawn cup known as earing. The optimization of cylindrical cup deep drawing process includes reduction of this undesired effect since it requires additional manufacturing operations and causes material loss. The objective of this paper is to consider earing minimization for extra-deep-drawing (EDD) steel sheet by modifying initial blank shape based on simulations of the process obtained by the finite element program ADINA. The material model utilized in performed simulations is based on associated flow rule, orthotropic Hill stress function and isotropic hardening law. Modifications of initial blank shape are performed by two approaches. By first approach, modified blank shapes are obtained by known simple analytical expressions based on Lankford coefficients. By second approach, modified blank shapes are obtained by using cubic B-spline curves. For the considered modified shapes, predictions of cup heights, equivalent plastic strain distribution, thickness strain distribution and required punch force are analyzed.

cylindrical cup deep drawing ; earing reduction ; plastic anisotropy ; optimization ; finite element method

nije evidentirano