气流热成像钢轨滚动接触疲劳裂纹在线检测与速度影响研究  

Study on the On-line Detection and Speed Effect of Rail RCFs Using Airflow Thermography

作　　者：陆小龙[1] 田贵云[2,3] 熊龙辉 高斌[2] 伍剑波[1] 苗玲 LU Xiaolong;TIAN Guiyun;XIONG Longhui;GAO Bin;WU Jianbo;MIAO Ling(School of Mechanical Engineering,Sichuan University,Chengdu 610065;School of Automation Engineering,University of Electronic Science and Technology of China,Chengdu 611731;School of Engineering,Newcastle University,Newcastle NE17RU UK;Infrastructure Inspection Research Institute,China Academy of Railway Science Co.,Ltd.,Beijing 100081)

机构地区：[1]四川大学机械工程学院,成都610065 [2]电子科技大学自动化学院,成都611731 [3]纽卡斯尔大学工程学院,英国纽卡斯尔NE17RU [4]中国铁道科学院集团有限公司基础设施检测研究所,北京100081

出　　处：《机械工程学报》2021年第18期98-106,共9页Journal of Mechanical Engineering

基　　金：国家自然科学基金(61527803);四川省国际科技创新合作(2021YFH0036)资助项目。

摘　　要：已有研究结果表明随着铁路行业对钢轨表面缺陷检测速度要求的不断提高,速度已经成为影响主动成像检测结果评定的主要因素。针对该问题,基于前期气流热成像在静态和低速下检测钢轨表面缺陷的研究,通过优化气流激励源、热像仪和试件之间的空间布局,激励源和热像仪的参数,提出以空间换时间策略消除速度影响抑制方法。研究不同检测速度下选择不同采样帧频和曝光时间时气流热成像和涡流脉冲热成像的速度影响。试验结果表明,红外热像仪的曝光时间和采样帧频选择与速度有关,通过优化激励源、热像仪和试件的空间位置,选择合适的曝光时间和采样帧频,结合热像处理算法可以消除速度和试件表面发射率的影响,在高达81.6km/h的检测速度下,气流热成像可以准确地检测出转盘边缘圆柱面上6种倾斜角度的人工裂纹,验证了以空间换时间策略的可行性。气流热成像具有较大的提离距离,与涡流脉冲热成像在表面及亚表面检测形成互补,在钢轨滚动接触疲劳裂纹在线快速检测有较好的应用前景。The existing research show that with the continuous improvement of rail surface defect detection speed in railway industry,the speed effect has become the main factor affecting the evaluation of active imaging detection results. To address the problem, based on the previous research of detecting rail surface defects under static and low speed by using airflow thermography, it is proposed that the speed effect can be eliminated by optimizing the space layout between the airflow excitation source, infrared camera and the specimen, and the parameters of excitation source and the infrared camera. The velocity effect of airflow thermography and eddy current pulse thermography with different sampling frame rate and exposure time under different detection speeds are studied.Experimental results show that the exposure time and sampling frame frequency of the infrared camera are related to the speed. By optimizing the spatial layout of the excitation source, infrared camera and specimen, selecting the appropriate exposure time and sampling frame rate, combined with the thermal image processing algorithm, the effects of speed and surface emissivity of the specimen can be eliminated. At a detection speed of up to 81.6 km/h, the artificial cracks with six inclined angles on the cylindrical surface of the edge of turntable can be accurately detected by airflow thermography. The feasibility of the strategy of swapping space for time has been verified. The air flow thermography has a larger lift off distance. Complementary with eddy current pulse thermography in surface and sub-surface detection, it is has a good application prospect in the field of on-line rapid detection of rail rolling contact fatigue cracks.

关 键 词：气流热成像 滚动接触疲劳裂纹 速度影响 表面发射率 

分 类 号：U216.3[交通运输工程—道路与铁道工程]