Performance evaluation and optimization analysis of series-augmented electromagnetic railguns using a multiphysics coupling model

• A multi-physics coupling model is proposed to guide the structural optimization design of series-augmented electromagnetic railguns. • The eight-rail configuration enhances energy conversion efficiency, achieving a remarkable 30.94% improvement in muzzle velocity. • The contact behaviors between the armature and rail affect the launch performance of electromagnetic railguns. . Electromagnetic railguns convert electromagnetic energy into kinetic energy to propel projectiles to hypervelocity regimes, establishing them as cornerstone technologies for next generation weapon systems requiring high-precision, long-range strike capabilities. To further enhance the muzzle velocity of the projectile, series-augmented railgun configurations have been presented to optimize the energy density, addressing conventional constraints on acceleration efficiency. This study proposes a multiphysics coupling model, integrating H-formulation and an arbitrary Lagrangian‒Eulerian method, to evaluate the electromagnetic-thermal-mechanical performance of series-augmented electromagnetic railguns and guide their structural optimization design. The contact resistance and contact thermal conductance at the armature-rail interfaces are calculated using the energy variational method and the Cooper-Mikic-Yovanovich method, respectively. Moreover, the friction at the armature-rail interfaces is also considered in the simulation. The magnetic field and temperature estimated by the simulation are in agreement with those measured experimentally for conventional two-rail railguns. The computational results demonstrate that adopting an eight-rail architecture not only elevates the energy conversion efficiency but also boosts the muzzle velocity of the projectile to 30.94% above that of a two-rail railgun, thereby validating the performance advantages of multirail configurations in electromagnetic launch systems. The effect of the number of rails on the fatigue life of the armature is discussed. Thermal analysis also reveals that the accumulation of localized heat at the armature-rail interface is caused by the friction between the armature and rails. This work provides a theoretical framework for multiphysics optimization in the design of series-augmented electromagnetic railguns. .