A circuit-motion-thermal-wear coupled model for performance prediction of electromagnetic rail launching

In electromagnetic launch system, the armature is highly susceptible to wear due to the extreme stress and heat conditions. To support accurate prediction of launch performance including wear amount, muzzle velocity, and contact stability, this study develops a predictive model that considers circuit response, armature dynamics, thermal effects, and wear evolution. The model incorporates temperature-dependent material properties, including electrical conductivity and thermal expansion coefficient, and accounts for the dynamic distribution of interfacial heat sources at the armature-rail contact. The calculated wear depth is validated under varied launching energy levels via in-situ X-ray flash radiography. The dynamic contact force including electromagnetic, preload, and reverse forces serve as an indicator for transition. By taking a contact force threshold of 10 N/kA, the model demonstrates its ability to predict pre-transition behavior and to evaluate the likelihood of transition. Based on this model, a study on current waveform regulation is carried out to compare the launch performance under different trigger timings with equal stored energy, and it is found that a long-duration flat-top current effectively suppresses armature wear and enhances contact stability. Experimental validation shows an increase in muzzle velocity without transition using this strategy.