Analysis of non-destructive testing of three-dimensional braided composites using scanning SQUID NDT.

The aim of this study is to provide an adequate understanding of the damage mechanism of three-dimensional braided composites based on offline measurements using the superconducting quantum interference device (SQUID) technique. This paper presents research into SQUID flux imaging for 3D braided composites under impact energy. Experimental results show that SQUID flux imaging can be considered as a suitable technique to detect defects of three-dimensional (3D) braided composites subjected to different energy impacts. When the deformation degenerates into internal cracking, the magnetic field signals decrease. The method provides an accurate calculation of the location of defects. The method will not only locate a defect, but can also be used for determining the internal characteristics of 3D braided composites, such as the braiding fibre orientation. Compared with the ultrasonic testing technique, the SQUID method is a more suitable non-destructive testing technique for 3D composite materials. This study shows that the SQUID testing technique is an effective tool for inspecting the state-of-failure of 3D braided composites. [ABSTRACT FROM AUTHOR]