基于热成像的高速铁路轨道板表面裂缝检测方法研究

Research on The Surface Crack Detection Method of High-speed Railway Track Slab Based on Thermal Imaging

针对高铁检修天窗的轨道板表面裂缝检测问题,采用红外热成像方法进行研究。首先,通过实际调研,确定了轨道板表面裂缝的主要表现形式和结构特征。其次,基于红外热成像检测原理,推导轨道板表面温差计算公式,得到裂缝检测的控制性因素。在此基础上,建立了含表面裂缝轨道板红外热成像检测有限元三维模型,分别研究了环境温度、裂缝宽度和裂缝长度对检测效果的影响,最后,通过对不同热激励辐射强度和激励时间的仿真计算,优化了检测条件,提高了检测精度。研究结果表明:利用热成像技术可以实现对轨道板表面裂缝的夜间检测,且环境温度越高、裂缝尺寸越大,检测效果越好。在20℃条件下,可以实现对宽度大于0.1 mm,长度大于15 cm裂缝的有效检测。在施加热激励辐射强度为1 000 W/m^2的条件下,可以实现对细小裂缝5 km/h的动态检测。

To detect track slab surface cracks in high-speed rail maintenance time,thermal imaging method is proposed for research.First of all,the main manifestations and structural features of surface cracks of the track slab are determined through field investigations.Secondly,based on the principle of infrared thermal imaging detection,the formula for calculating temperature difference of the track slab surface is derived,and control factors in crack detection are obtained.On this basis,the finite element three-dimensional model of infrared thermal imaging of track slab with surface crack is established,and the effects of ambient temperature,crack width and crack length on the detection results are studied.Finally,through simulation calculation of different thermal excitation radiation intensity and excitation time,detection conditions are optimized and detection accuracy improved.Research results indicate:nighttime detection of cracks on the surface of the track slab can be realized with thermal imaging technology,and the higher the ambient temperature,the larger the crack size,the better the detection effect.Under the condition of 20℃,effective detection of cracks with width greater than 0.1 mm and length greater than 15 cm can be achieved.Dynamic detection of fine cracks can be achieved by 5 km/h under the condition that the thermal excitation radiation intensity is 1000 W/m^2.