采用GJ-Ⅲ型扣件地铁轨道的钢轨波磨形成机理

Formation Mechanism of Rail Corrugation on Metro Track with GJ-ⅢFastener

在调研和测试我国8条采用GJ-Ⅲ型扣件地铁轨道中钢轨普遍出现短波长波磨特征的基础上,采用隐-显式有限元法,建立并验证考虑钢轨短波长凹陷激励的三维轮轨滚动接触有限元模型;通过模型求解不同波长钢轨凹陷和车速激励下的轮轨高频振动特性,并结合模态分析法、力锤敲击法和白噪声激励法探明显著高频振动来源,从动力类成因角度解释采用GJ-Ⅲ型扣件轨道的钢轨波磨形成机理和磨耗特征。结果表明:在25~60mm短波长凹陷和不同车速激励下,轮轨垂向力显著频率和白噪声激励下的钢轨垂向振动显著频率,与波磨通过频率吻合;车轮以75,85,95,103 km·h^(-1)速度滚过短波长凹陷钢轨后形成的钢轨不平顺显著波长分别为31.5,31.5和40,40,40和50 mm,与线路测试得到的钢轨波磨波长吻合;采用GJ-Ⅲ型扣件轨道的波磨并非钢轨1阶Pinned-Pinned共振引起,而主要是由570~720 Hz内的钢轨垂向弯曲高频固有特性被激发所致。

On the basis of investigations and tests of the characteristics of rail short-pitch corrugation commonly found in eight metro tracks using GJ-Ⅲ fastener in China,a three-dimensional finite-element model of wheelrail rolling contact considering the excitation of rail short-pitch dent was established and validated using the implicit-explicit finite-element method.The FE model was employed to solve the high-frequency vibration characteristics of wheel-rail under different wavelength rail dents and vehicle speed excitations.Combined with the modal analysis method,force-hammer excitation method and white noise excitation method,the source of significant high-frequency vibration was explored,and the formation mechanism and wear characteristics of rail corrugation with GJ-Ⅲ fastener were explained from the perspective of dynamic cause.The results show that under the excitations of 25-60 mm short-pitch dents and different vehicle speeds,the significant frequency of wheel-rail vertical force and the significant frequency of rail vertical vibration under the excitation of white noise coincide with the corrugation passing frequency.The significant wavelengths of rail irregularities developed after the wheel rolls over the short-pitch rail dent at the speed of 75,85,95 and 103 km·h^(-1)are 31.5,31.5 and 40,40,40 and 50 mm respectively,which coincide with the rail corrugation wavelengths from line tests.The corrugation of GJ-Ⅲ fastener track is not caused by the first-order Pinned-Pinned resonance of the rail,but is mainly caused by the excitation of the high-frequency inherent characteristics of rail vertical bending within 570-720 Hz.