基于脉冲激光点光源热成像方法检测钢材表面裂纹

Detection of steel surface cracks based on pulsed laser point source thermal imaging method

在损伤之前检测和表征钢材上的表面裂纹是一项非常重要的任务,对于涉及相关的结构安全有重大意义。本文采用了一种非接触式的脉冲激光点光源热成像技术,用于检测钢结构试件的表面破裂裂纹。使用脉冲点激光源将热量加载到材料表面,热流在传导过程中会受到裂纹缺陷的影响,裂纹的边界处阻挡的热流导致表面产生了明显的温度差,红外热像仪实时监测表面温度场的变化来实现裂纹缺陷的可视化。通过有限元仿真分析与实验验证的方法进行研究,结果表明:激励开始后,裂纹缺陷边界开始出现温度差,激励结束后,温度差达到峰值,实现裂纹缺陷的可视化;缺陷边界的温度差峰值以及出现时间与激励中心的距离相关。同时为下一步的定量检测奠定基础。

The detection and characterization of surface cracks on steel prior to damage is a very important task and is of great significance for the related structural safety.In this paper,a non-contact pulsed laser point source thermal imaging technique is used to detect surface cracks in steel structural specimens.The pulse point laser source is used to load heat onto the surface of the material.The heat flow is affected by the crack defect during the conduction process.The heat flow blocked at the boundary of the crack causes a significant temperature difference on the surface.The infrared thermal imager monitors the surface temperature field in real time to visualize crack defects.The finite element simulation analysis and experimental verification method are carried out.The results show that after the excitation starts,the temperature difference begins at the crack defect boundary.After the excitation is over,the temperature difference reaches the peak,and the crack defect is visualized.The temperature difference peak of the defect boundary and the time of occurrence is related to the distance of the incentive center.This study lays a foundation for the next step of quantitative detection.