高速铁路车轮的磨损与疲劳研究

近20年来，高速铁路得到了日新月异的发展，然而，对于高速铁路的关键性行走部件车轮，由于其服役环境是开放性的，并且伴随不断增加的车速及轴重，给车轮带来更加严峻和复杂的损伤。从轮轨接触问题出发，综述了高速铁路车轮主要损伤行为（磨损、疲劳）的现象及特点。由于轮轨接触面开放性的机械热交换作用而导致的车轮表面及近表面结构的热弹性不稳定性，是造成磨损的根本性原因；然而，与磨损缓慢的损伤过程不同，由材料成分和服役过程中机械载荷引起的应力大小和方向上的反复变化，诱发了疲劳源的萌生与裂纹扩展，且形式多样、破坏性更大。通过运用材料的塑性流变特性对车轮近表面的热弹性和内部织构的分析，归纳、总结了与磨损、疲劳等力学性能劣化相关的车轮材料组织、结构的响应特征，为车轮成型设计与服役安全评估提供了理论支撑。

A Study on Wear and Fatigue of High-speed Railway Wheels

During the last two decades, high-speed railway has been developing rapidly. However, as the key walking part of high-speed railway, wheels with characteristics of open service environment and the increase of vehicle speed and axle load, have suffered more severe and complex damage. Starting from the wheel/rail contact problem, main damage behaviors of highspeed railway wheels, such as wear and fatigue, are summarized. It is found that thermal elastic instability beneath wheels tread caused by mechanical heat exchange between wheels and rails, is the fundamental reason of wear. However, unlike slow damage process of wear, repeated changes of stress magnitude and direction caused by material composition and mechanical loading during service lead to fatigue initiation and propagation, and forms of wheel fatigue are more various and destructive. Based on the analysis of thermal elasticity and internal texture of surface/sub-surface materials by using the plastic rheology theory, wheel characteristic responses of microstructure related to wear and fatigue degradations are revealed, which provides a theoretical support for wheels molding design and service safety assessment.