Abstract：Traditional ultrasonic nondestructive detection techniques need to compare response data of a cracked component and a nondestructive one and analyze differences between them to identify crack. Two measured results are easy to be affected by manual operation error and changes of external environment, which causes the false detection of cracks. Here, a micro-crack quantitative detection technique for metal component surface based on laser ultrasonic was proposed to tackle this problem. This technique didn’t need to refer to response data of a nondestructive component, and crack quantitative detection was realized through extracting changes of nonlinear characteristic parameters after interaction between laser ultrasonic wave and a cracked component to avoid false detection of cracks. Laser was used to irradiate a component and excite ultrasonic wave. The component’s time domain dynamic response signals were used to reconstruct a phase space. A nonlinear characteristic parameters extracting method was introduced to evaluate the state space change between adjacent radiated points on the component, and realize crack detection. A test system was built to detect actual sand hole defects and fatigue cracks on the cylinder block surface of an air compressor. The results showed that the proposed technique can be used to effectively and quantitatively detect micro-crack on metal components’ surface.
刘永强，杨世锡，刘学坤. 基于激光超声的金属构件表面微裂纹定量检测技术研究[J]. 振动与冲击, 2019, 38(19): 14-19.
LIU Yongqiang,YANG Shixi,LIU Xuekun. Micro-crack quantitative detection technique for metal component surface based on laser ultrasonic. JOURNAL OF VIBRATION AND SHOCK, 2019, 38(19): 14-19.
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