Wheel-rail dynamics under transverse seismic excitation: material and speed effects

As high-speed rail networks extend into regions of severe seismicity, accurately characterizing wheel-rail contact behavior under transverse earthquake loading becomes imperative for operational safety. This study develops an explicit three-dimensional finite-element model of a high-speed train running on a CRTS III slab track and validates it against full-scale shaking-table tests. Using the validated model, we conduct the first systematic parametric study of (i) wheel-material constitutive behavior—rigid, linear-elastic, and elastoplastic, (ii) seismic intensity and frequency content, and (iii) train speed (150–300 km h−1) on a wheel-rail interface dynamics and contact-patch evolution. The results show that wheel material nonlinearity is negligible under low-intensity earthquakes, but moderate-to-high-intensity, low-frequency ground motions induce pronounced yielding. Compared with the elastic wheel, the elastoplastic formulation predicts peak lateral contact forces ≈20% higher, whereas the rigid assumption underestimates them by ≈60%. Transverse seismic excitation amplifies lateral forces sufficiently to activate the derailment sequence “wheel climb → wheel lift → wheelset impact → complete derailment.” Increasing train speed transforms the contact patch from a single ellipse into a bimodal footprint elongated in the running direction, enlarging slip regions and escalating the likelihood of wear, rolling-contact fatigue, and derailment. The proposed explicit-dynamics framework captures the coupled rolling-contact phenomena unique to seismic excitation and furnishes critical data for the seismic design, performance assessment, and safe operation of high-speed railway systems.