Defect Detection in Aramid Fiber-Reinforced Composites via Terahertz Radiation

Abstract

This paper presents the ability of Terahertz (THz) radiation in the non-destructive testing of composite materials used for military applications in ballistic protections. The terahertz scanner was used to detect the defects in selected elements consisting of aramid fiber-reinforced composites. Two sources of terahertz radiation, operated at frequencies 100 GHz and 300 GHz, were chosen. The results were next compared with the one obtained via X-ray imaging. The preliminary results showed that the THz radiation has high potential as the detection method in these materials. There is a significantly higher resolution of the results obtained at a frequency 300 GHz in comparison to 100 GHz. Moreover, THz waves alloweddetecting defects invisible to X-rays. The use of a high-quality THz scanner led to the efficient inspection of investigated areas and confirmed the presence of defects such as cracks, delamination, lack of material, and shrinkage of the material’s interior proving the high applicability of THz radiation in the monitoring of military designated-composite materials.