车轮踏面动态感应热成像缺陷检测方法研究

Research on dynamic induction thermography defect detection for wheel treads

涡流脉冲热成像是一种新型的无损检测技术,具有检测速度快,灵敏度高,探测范围大的特点。为适应车轮踏面缺陷的动态检测,本文提出了一种适应车轮踏面廓形的矩形磁轭电磁感应激励传感结构。通过传感器结构的磁路模型推导,从理论上证明了传感结构的可行性。通过数值模拟计算分析了踏面表面检测区域的磁场与涡流场分布,并对比了矩形磁轭与直导线的检测结果。在此基础上,本文搭建了一套车轮自动探伤检测系统,能够实现65 mm/s速度下的缺陷动态测量。结果表明,设计的矩形磁轭传感结构可优化感应加热的均匀性,对车轮踏面浅表层疲劳裂纹(轴向表面开口)具有更好的检测结果。

The eddy current pulsed thermography is a new technique for defect detection with high detection speed,high sensitivity,and large detection range.To adapt the dynamic detection of wheel tread,this article proposes a rectangular electromagnetic induction excitation sensing structure.By deducing the mathematical model of the magnetic circuit of the sensor structure,the feasibility of the sensor structure is proved theoretically.Through numerical simulation,this study analyzes the distribution of electromagnetic and eddy current field in the cracked area of tread surface.And the detection results of the straight coil are compared.Based on this,an automatic wheel flaw detection system is established,which is capable of dynamic measurement of defects at 65 mm/s speed.The results show that,by optimizing the induction heating uniformity of the wheel tread,the rectangular yoke sensing structure improves detection results for fatigue cracks in the shallow surface of the wheel tread(axial surface opening).