太赫兹时域光谱技术检测复合材料与金属的脱粘缺陷

Detection of the Debonding Defect between a Composite Material and Metal Based on Terahertz Time-Domain Spectroscopy

基于太赫兹时域光谱技术,提出应用太赫兹脉冲成像技术检测胶接结构中的脱粘缺陷,研究泡沫材料PMI与钢板胶接结构脱粘缺陷的检测。实验采用反射模式,分别对粘合部分与脱粘部分进行数据测试,对比分析发现数据在时域和频域范围均有明显区别。对待测样品进行二维扫描,应用太赫兹时域信号的时间位置幅值、最大值、延迟时间和频域信号不同频点的幅值、所有频点幅值叠加值对待测样品进行成像。研究结果表明基于太赫兹时域光谱技术的太赫兹脉冲成像技术能够检测出泡沫材料PMI与钢板胶接结构的脱粘缺陷;应用太赫兹时域信号的时间位置幅值、最大值、延迟时间和频域信号不同频点的幅值、所有频点幅值叠加值进行成像的结果,均可以分辨出样品的脱粘缺陷;不同的数据信息的成像效果不同。

Based on terahertz time-domain spectroscopy, we propose a method to detect the debonding defect in a bonded structure by the terahertz pulse imaging technique, especially the debonding defect detection of a PMI（Polymethacrylimide） foam material and steel plate bonded structure. By the reflection mode, both bonded and debonded parts were tested. The signal differences between the bonded and debonded parts are obvious, both in the time and frequency domains. The sample was imaged by the amplitude value at different positions, maximum amplitude in the time domain, delay time in the time domain, andamplitude values at different frequencies, and even with amplitude accumulation of all frequencies. Results indicate that the terahertz pulse imaging technique, which is based on terahertz time-domain spectroscopy, can detect the debonding defect of a PMI foam material and steel plate bonded structure. In all images obtained using the different data, the debonding part is clearly distinguishable; however, the imaging quality is different.