中文摘要：

疲劳断裂是金属结构的主要失效形式，通过金属疲劳断裂时声发射特征参数的提取，建立了声发射特征参数和裂纹扩展速率之间的关系，由试样的三点弯曲疲劳试验，证明采用声发射技术监测疲劳裂纹的扩展，不仅与疲劳裂纹扩展的变化规律相似，而且能实时的捕捉到疲劳裂纹的产生。

英文摘要：

Fatigue fracture is the main style of failure in metal structure. To extract the features of the detected crack, two equations are cited to set up the correlation between AE parameters and crack propagation velocity. According to the experimental results of three-point bending specimen, acoustic emission techniques monitoring fatigue crack propagation is ce~ificated not only to resemble variable rule of fatigue crack propagation, but also to catch generation of fatigue crack in real time.