间隙配合变轨距轮对与轨道间瞬态滚滑接触模拟研究

变轨距技术是实现不同轨距铁路联运的重要手段,我国相关研究仍在起步阶段。基于显式有限元法,建立包含渐开线花键副的三维变轨距轮对-轨道耦合瞬态分析模型,于时域内模拟速度高至400km/h下的瞬态轮轨滚滑和花键间动态接触行为及其相互影响。模型充分考虑轮轨和花键副三维几何、系统高频结构振动等,引入时变牵引/制动转矩,采用集成库仑摩擦定律的"面-面"接触算法求解轮轨接触和花键接触。假设圆柱直齿渐开线花键,齿数取32,齿侧间隙恒0.1mm,无激励下模拟结果表明,花键副的存在使得轮轨力波动范围大于传统轮对,例如,400km/h下法向轮轨力波动幅值增加静载的3.7%。时速400km/h和牵引系数0.05下,内外花键的径向和角向偏置使得花键左、右两侧各存在1个位置相对固定的承载区,各涉及5～6个键齿,承载面分别为II和I键齿工作面。瞬态法、切向接触应力极值发生在靠近一系悬挂侧的齿根或齿顶部,典型值分别为102MPa和4.6MPa,任一键齿的应力极值因不断有键齿进出承载区而波动上升和下降。牵引系数0.3时,左侧承载区消失,右侧承载区扩至18个键齿,相同时刻下的法、切向接触应力极值因承载齿数和总接触面积增加...

Transient Simulations of Gauge-adjustable Wheelset-rail Rolling-sliding Contact in Consideration of the Clearance Fit

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.