Development of coupled finite element model to investigate electromagnetic forming and simultaneous multi-point perforations of Aluminium tube

The paper presents a coupled 3D numerical model to understand high-strain rate electromagnetic forming and multi-point perforation of Al6061-T6 tube. This study focuses on a comprehensive exploration of the process by numerically simulating the forming and perforation of Al6061-T6 tubes for two type of punches (concave and pointed) across different configurations (12-holes and 36 -holes), and for two specific hole positions (centrally located and end holes), implemented through LS-DYNA™ software. A detailed analysis of the temporal distributions of various critical process parameters i.e., Lorentz force distribution, velocity on deformation, stress, and strain distribution near the perforated hole has been carried out to elucidate the physics of EMFP. Furthermore, the study compares the numerical simulation with experimental data to evaluate the number of perforated holes and the average hole diameter across different punch configurations and discharge energy ranges. The numerical outcomes are in good agreement with experimental findings, with maximum variations not exceeding 6%. The study also reveals that the non-linearity associated with Lorentz force distributions is not only in circumferential direction but also in axial directions. Higher energy levels increase hole diameter, but for the given tube geometry, maximum 6.2 kJ can be applied without occurrence of crack and rebound. For the given tube thickness, 6.2 kJ discharge energy is optimum to produce clear perforation.