锁相红外热像技术由于其实时、快速、无损以及非接触等优点，被逐渐应用于疲劳研究中。基于锁相红外热像理论，用法国Cedip公司开发的锁相红外热像系统对含缺陷的疲劳试件进行了无损检测，并快速测得了其疲劳极限。结果表明，相位图比幅值图能提供更多的缺陷内部信息，恰当选择检测频率是无损检测的关键，缺陷面积越大检测精度越高。随缺陷深度的增加，疲劳试件的疲劳极限降低。

Lock-in infrared thermography method is gradually used in fatigue studies because of its advantages such as real-time, quick-reaction, non-destructive, non-contact and so on. Non-destructive testing is applied to fatigue specimen with defects, and the fatigue limit is detected rapidly based on lock-in infrared thermography. In parallel, the results are analyzed using lock-in infrared thermography system developed by Cedip in French. It shows that more information of internal detects can be found from phase image than from amplitude image. The experimental procedure indicates that a proper testing frequency is the key to the non-destructive testing. The datas reveale that larger area of defect leads to a precise testing result and the fatigue limit of the specimen decreases with the increase of the defect depth.