Electromagnetic partitioning forming and springback control in the fabrication of curved parts

Abstract

The skin of an aircraft contains curved surface, which is a key component that determines its aerodynamic shape. During the manufacturing of its skin-parts, large springback often occurs, when conventional forming methods are used. Electromagnetic forming can reduce the springback substantially. In addition, the forming process enables moving coil discharge, which can be used to form large parts. In this study, an electromagnetic partitioning forming method is proposed that facilitates precise manufacturing and precise springback control of a single curvature part. A numerical simulation was used to analyze sheet deformation and stress - strain distribution in the sheet. Numerical simulation was also used to analyze the springback for both pure bending with large bending radius and electromagnetic partitioning forming. The simulation reveals that pure bending with large bending radius causes mainly elastic deformation in the sheet, while electromagnetic partitioning forming converts elastic deformation into plastic deformation. In addition, the residual stress on the sheet, after coil discharge, is small. Both experiment and simulation show very large springback in sheets that are subjected to pure bending with large bending radius but only small springback in sheets that are subjected to electromagnetic partitioning forming.