Abstract: The gauge-adjustable wheelset is a feasible means to realize the railway transportation over networks with different gauges, and the relevant research is still in its infancy in China. Using the explicit finite element method, a 3D gauge-adjustable-wheelset-track coupled model is developed, in consideration of an involute spline between the wheel and its axle, to simulate in the time domain the transient wheel-rail rolling-sliding contact and the dynamic contact in the spline and their interactions at speeds up to 400 km/h. 3D geometry of the wheel-rail and spline, high-frequency structural vibrations of the system and a time-varying traction/braking torque are all taken into account. The wheel-rail and spline contact are both solved by a surface-to-surface contact algorithm with the Coulomb friction integrated. The results show that under the condition of a straight cylindrical spline with 32 teeth, a constant flank clearance of 0.1 mm and no irregularities exciting, the resulting wheel-rail contact forces fluctuate fiercer than those of the integral wheelset, for example, the fluctuation of the vertical contact force increases by 3.7% of the static load at 400 km/h. Due to the parallel and angular misalignment of the spline, circumferentially, two zones of the spline are under contact under a traction coefficient of 0.05, being on the left and right sides and relatively stable in location, and each part covers 5-6 teeth with different working surfaces (II and I surfaces, respectively). The maximum pressure and tangential contact stress, occurring on the side of the primary suspension and at the root or on the top of a tooth, are typically 102 MPa and 4.6 MPa, respectively, at 400 km/h. As the teeth move in and out of the bearing zones continuously, the maximum stresses occurring on a tooth vary significantly during loading and unloading processes. At the traction coefficient of 0.3, the left bearing zone disappears and the right expands to 18 teeth, and the maximum pressure tangential contact stresses change to 89 MPa and 5.2 MPa, respectively, because of the increase of bearing teeth and total contact area on these teeth. This work provides an appealing tool for the strength and dynamics analyses and design of spline in future gauge-adjustable wheelsets.

Key words: gauge-adjustable wheelsets, spline pair, contact stress distributions, Von Mises(V-M) equivalent stress, explicit finite element method