Rate-Temperature Coupled Deformation Mechanism and Constitutive Parameters of Catenary Copper-Magnesium Alloy Materials for High-Speed Railway

With the continuous increase of train speed, the impacts of mechanical shock, arc heat, and Joule heat on the high - speed railway catenary system have become increasingly prominent. The coupling effect of high temperature and impact load has become a key limiting factor for the safe service of the pantograph-catenary system. This study focuses on the copper-magnesium alloy materials used in the catenary system to address the dynamic impact and friction-induced heat generation problems in high-speed railways. To explore the mechanical properties of the high - speed railway pantograph - catenary system under service conditions like dynamic impact and frictional temperature rise, a DF14.205D electronic universal testing machine and a split Hopkinson pressure bar (SHPB) were utilized. The uniaxial compression mechanical properties of the copper - magnesium alloy in the catenary were tested within a strain rate ranging from 0.001 to 3000 s⁻¹ and a temperature range of 293 to 873 K. The strain-rate effect and temperature sensitivity of the stress - strain response were carefully analyzed. The research also managed to reveal the compression deformation mechanism and the evolution law of the alloy's microstructure under the combined influence of strain rate and temperature. Moreover, a dynamic constitutive model was established to precisely depict its plastic flow behavior. Findings indicated that during compression, the copper-magnesium alloy materials displayed significant strain - rate strengthening and temperature softening effects. These effects were the result of the combined action of work hardening, strain rate, and temperature softening. At high temperatures, temperature softening mainly governed the material's deformation, and the temperature could stimulate the dynamic recovery (DRV) and dynamic recrystallization (DRX) processes. The modified Johnson-Cook (J-C) model was capable of accurately predicting the plastic flow stress-strain response. The research outcomes could offer valuable guidance and references for the safety design and evaluation of the high - speed train pantograph - catenary system during its service.