Modeling the Forming Process by Successive Local Deforming for Monolithic Stiffened Panels

Abstract The study considers a method for forming stiffened monolithic panels by local deformation of the panel ribs. The local deformation is caused by bending moments along the rib towards each other. The goal of the study is to numerically model the forming process of the stiffened monolithic panel utilizing the designed local-impact tool and analyze its effects on the panel, obtaining which experimentally is challenging. The finite element method (FEM) modeling is performed in ANSYS and validated by the experimental forming of a panel made of aluminum alloy analogous to Al 2024. Simulation results provide deformation, stress, and strain distributions along the panel in loaded and unloaded states for various study cases. Furthermore, the effects of finite panel length, width, and forming process parameters such as applied force couples and single versus successive deformation are numerically investigated and discussed. Performed modeling demonstrates the advantages of the forming with the designed tool in terms of low residual stresses and their distribution. Finally, the analysis suggests future modification of the tool, particularly the shape of its grips, to minimize local residual stress concentrations.