In-situ nondestructive inspection for detecting weld-defect during welding process of CFRTP

研制了一种可嵌入碳纤维增强热塑性塑料（CFRTP）焊接设备的涡流检测片。该薄板由一个激励线圈和若干个检测线圈组成。通过对激励线圈施加电压来加热样品。当存在焊接缺陷时，缺陷周围的温度从声音区域变化。由于电导率随温度的变化而变化，因此缺陷周围的电导率也与声区的电导率不同。通过测量检测区域的电导率分布，可以发现焊缝缺陷。利用人工焊接缺陷的CFRTP试样验证了该系统的可行性。结果表明，该系统能够以足够的精度检测焊缝缺陷。还研究了利用碳纤维布导电性的自阻焊接方法。

A eddy current inspection sheet which can be embedded in a welding equipment for carbon fiber reinforced thermoplastics (CFRTP) was developed. The sheet consists of an exciting coil and several number of detection coils. Specimens are heated by applying voltage to the exciting coil. When weld defect is present, the temperature around the defect is changed from sound area. Since electrical conductivity is chanded with temperature, electrical conductivity at around the defect is also changed from that of sound area. By measuring distribution of electrical conductivity of inspection area, weld defect can be detected. Feasibility of the developed system was examined by using a CFRTP specimen with artificial weld defect. The result shows the deveped system can be used for detecting weld defect with sufficient accuracy. Self-resistance welding method which utilizes the conductivity of the CFRP was also developed.