Multi-Physical Field Coupling Dynamic Numerical Modeling for Augmented Rail Launchers

Contact resistance voltage drop and back electromotive force generated during armature motion are the important parts of muzzle voltage of augmented rail launchers. An inversion method is proposed to accurately obtain the contact resistance between the armature and the rails and the mutual inductance gradient between the inner and outer rails, whose influence on the motion characteristics of augmented rail launchers is further analyzed. First, muzzle voltage, excitation current, armature velocity, and displacement are measured for the contact resistance calculation. Then, a modified adaptive annealing algorithm is used for the inversion of the contact resistance and mutual inductance gradient. Finally, an electromagnetic-force multi-physical field coupling dynamic numerical model for augmented rail launchers is established. The changes of the electromagnetic thrust and current density with the contact resistance and mutual inductance gradient are analyzed, and the calculated armature velocity is compared with the experimental one to verify the effectiveness of the proposed method.