Optimized Circular Coil Based Deperming Protocol of Naval Vessels Using Cage Systems

Naval vessels are made up offerromagnetic material which acquire permanent magnetism under the influence of the external applied magnetic field as well as earth's magnetic field. Deperming process is used to reduce the permanent magnetism in which objects are subjected to strong alternating decaying magnetic field. In traditional method, the entire vessel is tightly wrapped with coil in helical form. However, this method is constrained with geometrical impediments, number of windings and time consuming due to wrapping and unwrapping of individual vessel. In this paper, a deperming protocol with optimized solenoid and four circular coil cage systemsis proposed and comparative analysis is carried out. Experimental results show 99.91% homogeneity with greater accessibility of object and lesser number of windings as compared to wrapping based system. A deperming cage with feasible dimensions is designed and simulations are carried out with plausible choice of parameters. The analysis is based on finite element method having trajectory following hysteretic model which is used to showcase the effect of different cage systems.