为了研究轮对弹性振动模态阶数对轮轨动态作用的影响，以国内某型30 t轴重重载货车为研究对象。首先采用有限元方法建立不同模态的弹性轮对模型，在动力学软件中进一步集成为货车刚柔耦合动力学模型。采用时域、频域以及统计最大值的方法对比分析，发现轮对一阶横弯和车轮伞形振动模态能缓和轮轨横、垂向力，与此同时一阶横、垂弯模态会产生较大的纵向蠕滑力。最后分析了不同速度下各阶模态对动力学的影响。当轮对的一阶扭转、横弯以及二阶垂弯模态被激发时，速度变化对轮轨蠕滑力影响较大。对于轮轨横、垂向作用力，当轮对发生以一阶、二阶垂弯为主的振动时，速度对轮轨横向力的影响较为明显。 To study the influence of elastic vibration mode order of wheelset on wheel-rail dynamic interaction, a 30 t axle-load wagon was taken as the research object. Firstly, the elastic models of wheelset with different vibrating modes were established by using the finite element method, which were introduced into the dynamic software to constitute the rigid-elastic coupling dynamic model of freight wagon. The time domain, frequency domain and statistical maximum analysis methods were applied. It was found that, the first-order lateral bending mode of wheelset and umbrella-type vibration mode of wheels could ease the wheel/rail lateral and vertical forces. Meanwhile, the first-order horizontal and vertical bending modes would produce larger longitudinal creep forces. Finally, the influence of different modes on the dynamics at different speeds was analyzed. As the first-order torsion, lateral bending and second-order vertical bending modes were excited, the change of velocity had great influence on the creep forces of wheelset. Comparing between the wheel-rail lateral and vertical forces, the speed change had the greater influence on the wheel-rail lateral forces when the first-order and second-order vertical bending vibration modes dominated in the wheelset.