Experimental investigation into the mechanism of the polygonal wear of electric locomotive wheels

Experimental and Numerical Investigation into Formation of Metro Wheel Polygonalization

“…As it is shown in Figure 2, the wheel wear exhibits a combination of several different orders, while the wheel eccentricity (1 st order) and polygonal wear of the 6-8 th order have the highest roughness level. Such wheel polygonalization is unlike that previously observed on high-speed trains [14][15][16][17][18][19]24] and electric locomotives [12,13]; the latter are always characterized by a regular harmonic waveform with a constant wavelength along the wheel circumference. is is probably because high-speed trains and electric locomotives in China tend to maintain a constant operating speed over long-distance operation, while the metro's operational speed varies frequently due to the short station intervals.…”

“…Under the large wheel/rail forces, the flexible modes of wheelset are more easily excited. And the flexibility of wheelset, especially the lower torsional and bending mode, would in turn affect the wheel/rail contact forces and creepages and may promote the formation of the polygonal wear [11,13,27,29]. In order to eliminate the possibility of polygonal wear caused by wheelset flexibility, the modes of the wheelset are calculated by the finite-element method, the wheelset is formulated as hexahedron solid elements with the total number of 191,078, and the boundary of the wheelset is assumed to be free, as shown in Figure 17.…”

“…Tao [12] reported polygonal wear measurements on more than 2000 wheels of seven different types of locomotive used in China; 18 th , 19 th , and 24 th order polygonalization dominated for wheels on two types of freight traffic locomotive. Further experimental investigation [13] suggested that wheelset first bending resonance may be the root cause of 18 th -19 th order polygonalization, while 24 th order polygonalization may be attributed to lateral bending resonance of the wheel disc. High-order wheel polygonal wear was observed on Chinese high-speed EMU train wheels; at operating speeds of 300 km/h, the wheel exhibited 18 th -20 th order polygonalization [14][15][16][17][18], while 23 rd -24 th order wheel polygonalization dominated under operating speeds of 250 km/h [19].…”

Study on wheel polygonization of a metro vehicle based on polygonal wear simulation

“…Polygonal wheels are observed in a broad range of railway vehicles, including metro vehicles [1,2] , high-speed vehicles [3][4] , locomotives [5] and freight wagons [6] . They are cause of increased dynamic forces and impacts at wheel-rail contact that have been investigated widely by means of simulation and field tests [7][8][9] and produce a very significant increase of vibration both in the vehicles and in the track, especially in vertical direction, ultimately resulting in reduced ride comfort, increase of noise and shorter life cycles of rails and vehicles.…”

Study on the P2 Resonance Frequency of Vehicle Track System

“…世纪 70 年代英国 Derby 铁路技术中心的 LYON 等 在研究车轮通过低接头、 焊缝或车轮擦伤时提出的， 并一直沿用至今 [1] 。其中， P1 力的频率在 500～1 000 Hz，是由簧下质量和轨道之间轮轨接触变形引起的 振动，P1 力作用时间极短，通常对轮轨表面造成损 伤。P2 力可视为簧下质量与轨道作为整体质量在轨 道弹性基础上的振动， 其频率范围为 20～100 Hz [2][3] ， P2 力作用时间较长，可向上传递给车辆部件，向轨 下传递至道床，对车辆和轨道系统的危害最大。实 际上，P1 力是由接头及扁疤等突出的表面缺陷引起 的冲击力，而线路上不可避免的轨道不平顺以及车 轮周向不圆顺均可能引起轮轨系统的 P2 共振， 因此， P2 共振普遍存在于车辆轨道系统，对轮轨界面的非 均匀磨耗有直接影响，GRASSIE 和 KALOUSEK 总 结的六种类型钢轨波磨中，重载型(Heavy haul)、轻 轨型(Light rail)及接触疲劳型(Contact Fatigue)波磨 均与 P2 共振有关 [4] 。KNOTHE 和 GRASSIE 称 P2 共振与波长为 300～1 500 mm 的钢轨波磨形成有 关， 在巴黎的 RATP 地铁线上出现了 P2 共振引起的 轻轨型波磨 [5] 。NIELSEN 等 [6] 指出随着轨道刚度的 增加， 由车轮多边形磨损激起的 P2 共振将加剧轮轨 动作用力，1～5 阶车轮多边形磨损可能与轮对 1 阶 弯曲和扭转固有频率以及 P2 共振有关。1998 年德 国 ICE 高速列车脱轨调查中发现脱轨列车车轮周向 具有 3 阶不圆顺磨损 [7] 。此外，P2 共振频率还可能 与车辆部件的弹性固有频率一致，如轮对的 1 阶弯 曲振动频率一般在 70～95 Hz(直线电机地铁轮对为 73 Hz [8] ，意大利 ETR 高速列车轮对为 79 Hz [9] ，ICE 轮对为 89 Hz [7] ，电力机车轮对为 84 Hz [10] )，车辆系 统部件的固有频率与 P2 共振频率接近时，强烈的 轮轨动作用将会导致车辆部件和轨道结构的疲劳 破坏。 轨道垂向振动固有频率首先由 TIMOSHENKO 于 1926 年通过无质量 Winkler 地基梁模型得到，可 表示为 ω R = (k/m) 0.5 ，其中，k 为 Winkler 地基刚度 系数(即钢轨基础弹性系数)，m 为钢轨的单位长度 质量。PATIL 在 TIMOSHENKO 研究基础上考虑车 轮质量的影响，指出车轮质量会降低轨道的固有频 率 [11] 。直到 20 世纪 80 年代人们才发现负载状态下 轨道结构存在 25～40 Hz 的低阶固有频率。英国铁 路发现轨道无载荷状态的 1 阶固有频率在 130 Hz 左右，当受到车轮簧下质量负载后的低阶固有频率 降至 50～80 Hz [5] 。GRASSIE 等 [12] 分别利用连续双 层梁模型以及离散轨枕支撑模型研究了垂向激扰作 用下的轨道振动，指出轨道系统存在钢轨和轨枕质 量在轨道整体刚度上的低阶共振，当轨道系统受到 350 kg 车轮质量作用时， 该共振频率从 150 Hz 降到 100 Hz 以内。CLARK 等 [13] 研究了波磨钢轨的轮轨 相互作用，通过传递矩阵法计算离散支撑轨道结构 的固有频率，得到的轮轨系统的低阶固有频率为 80.24 Hz。ONO 等 [14] 研究了连续支撑无限长轨道在车 轮冲击载荷下的自由振动和受周期不平顺激扰的强 迫振动。MÜLLER 等 [15] 通过傅里叶变换法和 Floquet 理论研究了离散支撑轨道在车轮载荷下的振动问 题，考虑簧下质量后车辆、轨道和轨枕整体同相振 动频率为 81 Hz。近三十年来国内外学者对车辆和 轨道垂向冲击和振动问题进行了大量的研究 [16][17][18][19][20][21][22][23][24][25] ， 李成辉等 [16] 研究了高速铁路受移动周期载荷的位 移波现象，结果表明，增大轨道阻尼可提高轨道临 界速度；ZHAI 等 [17] 提出了车辆轨道垂向耦合动力 学模型，轨道结构考虑了钢轨受轨枕和道床离散支 撑的影响，通过 Hertz 非线性接触理论与车辆模型 耦合；文献 [18][19][20]…”