基于直流电位降的高铁车轴裂纹检测研究

Research on Crack Detection of High-speed Railway Axle Based on Direct Current Potential Drop

车轴是高铁车辆走行部重要的部件之一,其在服役过程中产生的裂纹会严重影响车辆运行的安全性。目前还未实现实时在线检测,现场检修时采用超声和磁粉方法存在检测效率低、操作复杂等问题。直流电位降(Direct current potential drop,DCPD)检测方法可靠方便,能够克服上述问题。基于DCPD检测原理,建立裂纹检测数学模型,结合稳定直流电场的Laplace方程,运用ABAQUS建立带裂纹的全尺寸车轴三维有限元模型,对一系列带不同深度半椭圆裂纹的车轴进行仿真。分析裂纹区域电位降信号,研究全尺寸高铁车轴电位降与裂纹深度的关系,并绘制电位降随裂纹深度变化的校准曲线,讨论影响校准曲线的相关因素,发现裂纹面相对于轴线的偏转角度和探针的相对位置均会影响校准曲线选择。该研究结果为高铁车轴裂纹的实时检测提供了实现思路和方法。

The axle is one of the important parts of the running gear of the high-speed rail vehicle,and the cracks produced during the service process will seriously affect the safety of the vehicle operation.At present,real-time online detection has not been realized.The use of ultrasonic and magnetic particle methods for on-site maintenance has problems such as low detection efficiency and complex operation.The direct current potential drop(DCPD) detection method is reliable and convenient,and can overcome the above-mentioned problems.Based on the principle of DCPD detection,a mathematical model for crack detection is established and combined with the Laplace equation for stable DC electric field,uses ABAQUS to establish a three-dimensional finite element model of a full-scale axle with cracks,and simulates a series of axles with semi-elliptical cracks of different depths.The potential drop signal in the crack area is analyzed,the relationship between the potential drop of the full-size high-speed rail axle and the crack depth is studied,and the calibration curve of the potential drop with the crack depth is drawn,and the relevant factors affecting the calibration curve are discussed.It is found that the crack surface is relative to the axis.Both the deflection angle and the relative position of the probe affect the selection of the calibration curve.The research results provide real-time ideas and methods for real-time detection of high-speed rail axle cracks.