Numerical simulation and experimental results of the metal armature acceleration

A numerical model for calculating the contact pressure in EM rail launchers is developed. The calculation code is based on the solution of steady, axis-symmetrical contact springiness problem utilizing the finite element method. An experimental investigation was also carried out with the following parameters: (1) the power supply system was based on 5 MJ capacitor banks charged to 4.3 kV; (2) the rail accelerator had a bore length of 4.2 m and a bore diameter of 30 mm; (3) the rail material was bronze and the insulator material was fiberglass STB-3 (G-10 type); and (4) the preaccelerator was a conventional powder gun. The experimental results agree with the authors' understanding of armature physics at velocities of 2.1 to 2.7 km/s. The results can be improved with correct calculation of balancing forces that provide the necessary contact in the conducting part of the armature, and the normal pressure force, which is responsible for friction. The problem of 2-D and 3-D distribution of nonsteady electromagnetic heat and force fields in the fixed contact zone should then be solved.<
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