Modeling the temperature evolution of electromagnetic rails under multiphysics coupling

A three-dimensional transient electro–magneto–thermo–mechanical coupled model was developed to investigate the thermal response of the rail during launch, incorporating contact pressure, contact resistance, and friction at the armature–rail interface. The results are as follows: (1) In spatial distribution, the rail temperature rises first and then falls along the direction of armature movement, with the peak located in the low- to medium-velocity stage. (2) In spatial heat evolution, the temperature transitions from a rapid increase to a plateau stage and then to a gradual decrease. (3) As the launch progresses, Joule heating from contact resistance dominates at the beginning, follow K to 887 K. The model incorporates material thermal softening. This effect, combined with electromagnetic force attenuation, leads to a progressive decrease in contact pressure. The reduced pressure, in turn, results in higher contact resistance and intensifies localized heating, which ultimately accelerates the overall rail temperature rise. These findings clarify the coupling between current and heating sources, providing theoretical insight and numerical support for thermal protection design and service life assessment of electromagn ed by frictional heating, contributing approximately 62% and 38% of the total heat input, respectively. The peak rail temperature rises from 293 etic launchers. • A 3D transient multiphysics model is developed to simulate rail temperature evolution. • The model couples electromagnetic, thermal, mechanical, and contact phenomena. • Spatiotemporal characteristics of heat sources vary across launch phases. • High-temperature zones tend to appear in low-to-medium velocity segments. • Local thermal stress gradients may induce surface fatigue and microcracks.