锁相热像技术及其在无损检测中的应用

Lock-in thermography and its application in nondestructive evaluation

红外热波检测技术是一种新兴的无损检测技术。与传统的被动式红外检测方法不同,该方法将外加瞬时或交变温场施加到被测物,通过红外热像设备监测被测物在外加温场下的表面温度变化。根据外加温场的类型及相应的物理模型对采集到的数据信号进行处理,以图像的形式显示。锁相热像技术使用周期的交变温场与锁相处理方法,具有检测面积大、对表面加热均匀性要求低等特点。与多数锁相红外检测使用的正弦型热源不同,对方波加热红外热像检测系统的原理及验证性实验进行了介绍,并将该系统应用于碳纤维层压板冲击损伤的检测。结果表明:方波加热的锁相热像检测系统结构简单,对厚度不大的试件具有相当好的检测效果。

Infrared thermal wave inspection is a merging technology in nondestructive evaluation.Different from conventional passive infrared inspection,infrared thermal wave inspection works with a sample under transient or alternating temprature field.The surface temprature is recorded by a infrared camera,and the data collected is processed according to the type of the temperature field and correspond physical model.Lock-in thermography copes with periodical alternating temperature field and lock-in data process.This technology has features as large inspection surface and insensitiveness to uneven heating.Different from the most lock-in thermography with a sine-type heat source,the principle and validation experiment of square wave heating were introduced in this paper.This lock-in thermography was also applied in inspection of impact damage in carbon-fibre reinfored plate.The inspection result shows that square-wave heating lock-in thermogarphy is a simple and effective inspection method for samples with finite thickness.