超声源的位置对激发裂纹热成像的影响  

Effect of Position of Ultrasonic Excitation Source on Thermosonic Image of Cracks

作　　者：郑江[1] 郑凯[2] 张淑仪[1] 

机构地区：[1]南京大学声学所近代声学实验室,南京210093 [2]江苏省特种设备安全监督检验研究院,南京210003

出　　处：《无损检测》2009年第12期946-949,共4页Nondestructive Testing

基　　金：中国国家自然科学基金(10574073)

摘　　要：超声激发裂纹热成像是针对表面和亚表面裂纹及缺陷的无损评价和检测新技术。由于在强超声脉冲作用下,裂纹两边缘的振动幅度和相位不同而使裂纹区域温度升高。试验中观察到当超声源激发的位置改变时,裂纹区域的温度升高(加热)明显不同。根据超声在板中的传播理论,提出了一个理论模型来计算裂纹两边缘的振动。计算中考虑了多个谐波成分的传播,得到裂纹两边缘振动之间的振幅和相位差。这种差异与超声源和裂纹之间的相对方位和距离有关,而且引起裂纹区域不同的温度上升。最后,对结果进行了分析和讨论,理论计算与试验测量相符。Thermosonic imaging is a new kind method of NDE/T technique for detecting surface and subsurface cracks and defects. In the technology, the cracks （defects） will be heated under intensive ultrasonic pulses excitations due to both sides of the cracks have different vibration amplitudes and phases. In the experimental studies of the technology, it has been found that the cracks display obviously different temperatures （heats） while the ultrasonic excitation sources are located at different positions. On the other hand, based on the ultrasonic propagations in plates a theoretical model is presented to calculate the vibrations of both sides of the cracks, and the amplitude and phase differences between two vibrations of both sides of the cracks are obtained, in which the harmonic components are considered. The results show that the differences are dependent on the relative directions and distances between the ultrasonic sources and the cracks. The amplitude and phase differences of both sides of the cracks determine the temperatures （heats） around the cracks. Finally, the results are analyzed and discussed, which show that the theoretical calculations are in agreement with that of the experimental measurements,

关 键 词：超声红外热像 激发源位置 升温响应幅度 

分 类 号：TG115.28[金属学及工艺—物理冶金]