轮轨接触表面有液态介质时的接触问题研究
THE ANALYSIS OF RAIL-WHEEL CONTACT SURFACE WITH LIQUID
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摘要: 采用接触单元方法,结合初应力法,对于具有表面微观粗糙度和有液态介质存在于轮轨接触表面的弹塑性接触问题进行了研究,获得了轮轨表面接触压力分布、应力分布等结果。结果表明,它们都存在不同程度的峰值,且这些峰值比Hertzian 接触压力大许多,这是由于有表面微观粗糙度的存在,接触过程中凸出的部分进入了接触,而凹下的部分还未进入接触所致。对于法向接触压力,总的来说弹性计算结果的峰值比弹塑性计算结果的峰值要大。而且轮轨接触表面无液态介质存在时的弹塑性计算结果的接触压力峰值比有液态介质存在下的弹塑性计算结果的峰值要大,这是由于接触表面有液态介质存在时,在凹下的部位液态介质不易自由流动和不可压缩特性,引起了液态介质承受了压力所致。Abstract: The frictional contact problem between rail and wheel is analyzed by contact element method and initial stress method. The micro-roughness on contact surface, the liquid existing on rail surface and elastic-plastic property of material are considered. The distribution of contact pressures and stresses on contact surface is obtained for dry contact and contact with liquid. There exist a series of peak values of contact pressure that are much larger than the value of Hertzian contact pressure. This is because that only the protuberant part is in contact status but the concave part is not in contact status when the micro-roughness of contact surface is considered. The peak value of contact pressure is larger for elastic analysis than that for elastic-plastic anlaysis. In the case of elastic-plastic analysis, the peak value of contact pressure for dry contact surface is larger than that for contact surface with liquid. This is because the liquid on the contact surface is considered as incompressible, and the liquid would transfer force when it is restricted in a concave part of contact surface.