Contribution numérique et analyse comparative du retour élastique lors de la mise en forme d’un alliage d’aluminum Al5086-H111

Abstract

The objective of the study described in this thesis is to find solutions to the problems encountered in sheet metal forming such as the spring back problem. In the first part, an experimental study based on theoretical analysis. For this purpose, a major effort is made to add a new design of parts for a U-type stretch-bend device and adapt it to a tensile testing machine. This design has the advantage of modifying and assembling all the parameters affecting the spring back at the same time and also to perform several forming processes on the same device. Experimental and numerical prediction of spring back was performed, and also the study of the effect of various parameters of the stretch-bending and air-bending process, such as punch speed, sheet orientation (anisotropy), holding time and clearance between punch and die, etc., on the behavior of spring back during the heat treatment of aluminum alloy sheets with three different rolling directions (0°,45°,90°). The development and optimization of these processes requires numerical simulations and test bench studies. A finite element (FE) model of the two processes studied was established using the ABAQUS software. This analysis allows to conclude that the spring back is affected by several parameters in the process of stretch-bending and air-bending. The experimental results obtained were compared to the numerical simulations which were found to be in good agreement.