高速列车轮轴缩比关系及微动参量仿真分析

High-Speed Train Wheelset Axle Scaling Law and Fretting Parameter Simulation Analysis

车轴与车轮通过过盈配合组成轮对,承受着车辆的全部重量,是保证高速动车组运行安全的最重要部件.高速列车轮轴的疲劳周次长达109,实物轮轴试验的过程复杂、周期长且试验费用高.因此,通过缩比模型反映和预示实物轮轴试验结果具有极大的理论价值和工程意义.本文中结合相似定理和量纲分析原理,分析并推导了轮轴过盈配合微动参量随在不同缩比系数下的相似关系,采用ABAQUS有限元软件对微动参量分布进行仿真分析,结果表明,微动参量在不同缩比系数模型中的分布规律和理论推导的相似关系一致;轮轴接触压应力以及轴向摩擦剪切应力的最大值,位于车轴轮座区域靠近齿轮箱座的内侧,高速列车车轴轮座内侧接触边缘最容易发生微动疲劳失效.

The axles and wheels are assembled into a wheel set through interference fit,which bears the full weight of the vehicle,and is the most important part to ensure the safe operation of high-speed EMUs.The fatigue cyclic load cycles of high-speed train axles reach or even exceed 10~9,which leads to the problems of complex process,long time period and high test costs for physical axle tests.Therefore,it is of great theoretical value and engineering significance to construct dimensionless variables expressing the essential laws of physics and obtain the corresponding laws of physics by taking the existing physical problems as the research object,and to further reflect and predict the test results of real axle through the scale model.Based on the similarity theorem and the dimensional analysis method,this paper analyzed and derived the similarity relationship between the fretting parameters of the wheel-axle interference fit with different scaling factors.ABAQUS finite element software was used to verify the scaling relationship and carry out numerical simulation research on the distribution characteristics of fretting parameters.The results showed that the distribution of fretting parameters in different scaling coefficient models was consistent with the similarity relationship deduced theoretically;the maximum values of Mises equivalent stress,contact compressive stress,and axial frictional shear stress were located at the inner side of the axle wheel seat area near the gearbox seat,and the ratios to the outer side were 1.56,1.81 and 1.58,respectively,but the axial slip amplitude of the outer side was slightly larger than that of the inner side,so the high-speed train axle contact edge of the wheel seat inside the most proned to fretting fatigue failure.The maximum values of Mises equivalent stress,contact compressive stress and axial frictional shear stress in the interference fit area of the axle were 103.26 MPa,148.21 MPa and 10.22 MPa,respectively.The Mises equivalent stress and contact compressive stress were distributed in a"W"shape along the axial direction of the axle.The stress values at the contact edge were larger than those in the contact middle area,however,the stress values on the outer side of the axle contact are negative and the inner side values were positive,indicating that the frictional shear stress on the inner and outer sides of the contact area was opposite in the axial direction.The magnitude distribution of the axial slip amplitude at the relative position of the axle shaft satisfied the scaling law and was proportional to the scaling factor.The maximum value of the axial slip amplitude under the prototype axle was-7.84μm,which occured outside the contact.The section bending moments at the three contact positions of the axle wheel seat area also satisfied the scaling law,that was,it was proportional to the cube of the scaling coefficient,and the normalization coefficient defined in this paper was basically close to 1.In the wheel seat area of the axle,as the section moved from the outer edge of the wheel seat to the inner edge,the bending moment of the section increased continuously and reaches a maximum value at the inner edge of the wheel seat.