利用冲击疲劳损伤对材料微观结构和应力分布的改变导致的材料导热率和电阻率等参数变化的特性, 提出了利用涡流热成像技术检测金属材料冲击疲劳损伤的无损检测方法, 构建了检测系统。通过试验, 获得了飞机刹车片的涡流热成像图像。结合对冲击疲劳损伤引起的塑性变形而导致的材料导热率和电阻率等的变化的分析, 通过图像处理提取了试件的温升变化曲线,比对了受损区域和正常区域的红外图像差异, 实现了对冲击疲劳损伤缺陷的判别。结果表明, 涡流热成像法能够快速地判断材料受损位置。

Eddy current thermography has been applied to detect surface and near surface cracks of metal parts, which have high detection efficiency and capability of large one-time detection area. The heat conduction and resistivity of material can be changed by impact fatigue damage due to the change of microstructure and stress distribution of the material caused by impact fatigue damage. In this paper, eddy current thermography is employed to detect impact fatigue damage of metallic material. A detection system is established. The thermal image sequences of aircraft brake block have been captured with eddy current thermography. The images have been analyzed according to the principle of the change of thermal conductivity and resistivity caused by plastic deformation due to impact fatigue damage. The temperature feature and the deference between damage area and non-damage area have been obtained by processing the infrared images. The results indicate that the impact fatigue damage of metallic material components can be detected qualitatively. The damage area can be identified quickly for metallic material part by using eddy current thermography.