FE Analysis of Effect of Variation in Coil length and Coil-tube Relative Positions on Establishment of Magnetic Fields and Distribution of Velocities in Electromagnetic Forming of Muffler Tube

Abstract

The electromagnetic forming (EMF) process is a high energy rate process that uses magnetic forces to deform the metal workpieces. It also involves high velocities and high strain rates. It is tough to find out these process parameters experimentally, which proposes the need for numerical models. The EMF of muffler tube is a novel technique of manufacturing a single piece of component of the desired shape, which eliminates the disadvantages of conventional manufacturing techniques. This paper presents an FE model to observe the distribution of the magnetic field and velocities that drives the muffler tube. The coil-tube axial position is significant in the EMF process as the magnetic field produced is not uniform along the length of the coil. In the analysis of EMF processes, it is essential to able to estimate the magnetic field generated along the length of the coil. The presented coupled FE model can estimate the magnetic field and impact velocity generated during different coil-tube positions and discharge energies. The developed model is validated with deformation obtained in experimental runs. The simulation results show that to deform the aluminium tube minimum of 3 T magnetic field or a minimum of 87 m/s velocity is required. It is found that the coil having 100 mm length is giving more uniform pressure compare to other lengths. It is also observed that with the use of 100 mm length coil and amongst all coil-tube positions when offset between coil and tube relative position is zero, it develops the uniform distribution of magnetic field and velocities at a required area which results in maximum deformation compared to other positions. The development of such an FEA model helps to eliminate empirical investigation to discover the magnetic field and velocities involved in the process.