Papers by Keyword: Metal Sheet Forming

Abstract: Sheet Metal Forming is a widely used process in industry. However, it is also an expensive onedue to the diversity and complexity of methodologies used to obtain the adequate tools combination.In fact, even though there is already finite element based software to compute the final shape of aformed sheet from a given tool, there is no efficient procedure to predict the inverse problem: the toolgeometry from the formed component final shape.The final aim of this work is to improve the current trial-and-error process for the inverse problem.To achieve this objective, an integrated approach for tools geometry manipulation is presented, basedon the parametric NURBS description of the tools surface. This is applied to perform a sensitivityanalysis in order to evaluate the effect of numerical noise and small disturbances on the tools designvariables in the final formed sheet. Furthermore, the robustness of the proposed approach is evaluatedusing two parts with distinct complexity.

Abstract: Forming limit strains are used to construct a forming limit diagram (FLD), which is a diagram in the principal strain space, traditionally used for designing forming operations of sheet metals. A line indicating the boundary between safe and unsafe strains is often called the forming limit curve (FLC). FLDs are also used to evaluate results from finite element simulations. Therefore consistency and reproducibility are important. This paper deals with the experimental determination of forming limit strains from Marciniak-Kuczynski (MK) tests. The material tested is AA6016 aluminum alloy in three different conditions: virgin material and material subjected to 5% and 8% deformation by rolling. Strains were measured by the use of digital image correlation (DIC) technique. Forming limit strains were determined by the use of two automated methods. The results from the two methods are compared and evaluated regarding their applicability to the Marciniak-Kuczynski test and ability to capture actual forming limit strains.

Abstract: The main defect of shrink flanging wing rib is wrinkling in rubber bladder hydroforming. In the aeronautical field, the side blank holder is usually used to avoid wrinkling. In order to obtain appropriate parameters of side blank holder, it be carried out that the simulation analysis for the process of the high hydraulic press rubber forming processes of high shrink flanging with side blank holder by the ABAQUS finite element software. Besides, the corresponding experiments verified also be implemented. The research results show that the sheet metal tends to wrinkle along with decrease of the blank lap width and increase of these parameters such as the distance between side blank holder and die, the dip angle and fillet radius of the side blank holder.