Thermo-mechanical coupling in high-speed RDX collisions: How plasticity triggers hotspot formation

This study explores the thermo-mechanical coupling mechanism of cyclotrimethylene trinitramine particles during high-speed collisions by combining molecular dynamics simulations and an analytical model, with a focus on elucidating how plastic deformation triggers hotspot formation. Analytical models of particle collisions with varying sizes and velocities were established to analyze the evolution of contact forces and temperature increase during the collision process. Both numerical and analytical results demonstrate that plastic deformation is a key factor that leads to the localized temperature rise, featured by a universal correlation between the proportion of atoms in severely plastic deformed regions and high-temperature atoms, clarifying the quantitative relationship between plasticity and heating. Furthermore, the analysis of C–N bond evolution reveals how collision-induced plasticity initiates the potential chemical decomposition. This research provides a critical foundation for understanding mechanical–thermal transition during high-speed collisions of energetic materials.