The springback phenomenon that occur in thin metal sheets after forming is mainly a stress driven problem, and the magnitude is roughly proportional to the ratio between the magnitude of the residual stresses after forming and Young’s modulus. An accurate prediction of residual stresses puts, however, high demands on the material modeling. A phenomenological plasticity model is made up of sever...

For ̄ exible manufacture of a doubly curved sheet metal, a new sheet metal forming process is proposed that uses a movable punch set composed of two pairs of lower support punches and one upper centre punch. The process is characterized by ̄ exibility compared with the existing conventional processes because it does not require any complex-shaped die and the loss of material is minimized by unc...

This paper aims at experimental and numerical investigation of springback behavior of sheet metals during Lbending process with emphasis on Stribeck-type friction modeling. The coefficient of friction in Stribeck curve depends on sliding velocity and contact pressure. The springback behavior of mild steel and aluminum alloy 6022-T4 sheets was studied experimentally and using numerical simulatio...

1 2 2 2 3 3 Thomas Pressel, Anas Bouguecha, Matthias Kammler, Bernd-Arno Behrens, Ute Vogt, Andrea Meyer-Lindenberg, 1 Henning Windhagen 1 Department of Orthopaedic Surgery, Hannover Medical School, Hannover, Germany; E-Mail: [email protected], 2 Institute of Metal Forming and Metal Forming Machines, University of Hannover, Hannover, Germany 3 Clinic for Small Domestic Animals, School of Vet...

Purpose: In this paper the experimental equipment and design of the system for deformation and forming force measuring by single point incremental sheet metal forming are described. Beside this the analysis results of the impact of the wall angle, tool rotation, vertical step size, tool diameter and lubrication on the magnitude of forming force and plastic logarithmic strain are presented. Desi...

Deformation of the material during cyclic expansion extrusion (CEE) is investigated using upper-bound theorem. The analytical approximation of forming loads agrees very well with the FEM results for different amounts of chamber diameter, friction factor and also for lower die angles. However, the difference between analytical and numerical solution increases at higher die angles which are expla...

In this article, the effect of different yield functions on prediction of forming limit curve (FLC) for aluminum sheet is studied. Due to importance of FLC in sheet metal forming, concentration on effective parameters must be considered exactly in order to have better theoretical prediction comparing experimental results. Yield function is one of the factors which are improved by adding new coe...

Deep drawing of two-layer sheet is a suitable way to achieve product with a desired shape and desired properties in sheet metal forming technology. Control of deep drawing parameter such as thinning is the most important challenge in this process. The most difficult part of this challenge is differences in material properties and geometry of each layer. In this paper, numerical approach has bee...