涡流式电磁声发射检测声波响应特性

涡流式电磁声发射检测由于其局部非接触式加载方式,适用于恶劣环境下对金属构件损伤在线检测,同时也是对传统声发射技术的有利补充。针对不同电磁载荷条件下电磁声发射产生的声波响应问题进行深入研究。通过引入电致塑性理论和自由电子运动理论,分析涡流加载下裂纹尖端位错滑移速率变化及声发射能量释放机理,探究不同磁场方向加载下电子的定向移动对声发射响应影响,利用希尔伯特黄变换方法实现对声发射信号的特性分析。实验结果表明:电磁声发射过程中应力波特征与电磁加载条件密切相关。因此,电磁声发射过程为定向移动电子越过障碍势垒产生的特定声波响应。

Acoustic Response Characteristics of Acoustic Emission Induced by Eddy Current Exciting

Due to the contactless local loading of electromagnectic acoustic emission, this paper provides a method for the damage online inspection under severe working conditions, which is a beneficial supplement of traditional acoustic emission technology. This paper studies the acoustic response characteristics arising from electromagnetic acoustic emission under various electromagnetic loads. According to the electroplastic theory and free-electron theory, the mechanism of acoustic emission energy release and the rate variations of the crack tip dislocation slip are analyzed. Thus, the various acosutic responses of the electronic directional movement under different magnetic field directions can be obtained. The electromagnetic acoustic emission signal analysis based on Hilbert-Huang transform (HHT) is an effective tool to extract the features. The experimental results show the stress wave characteristics are closely related to electromagnetic loading. Therefore, this process is the specific acoustic response between the directional mobile electronic and obstacle barrier.