The Terahertz-based non-destructive evaluation of military-designated materials

Abstract

With regards to composite materials, the need for noninvasive evaluation of their structures, components, or systems they form continues to rise. It relates to the fact that composites, due to their two-phased (at least) composition, are vulnerable to different damages arising during their manufacturing or their use. Thus, there is a need to non-destructively monitor such materials especially when they are used in safety applications such as e.g., bulletproof vests and their damage may pose a real threat. In the frame of this work, the use of the newly developed non-destructive testing (NDT) method based on the application of Terahertz (THz) radiation was presented. For this purpose, the series of samples without defects and with a defect in their interior was investigated. The samples were prepared as the soft insert of a bulletproof vest and one of them had intentionally introduced defect in the form of aramid fibers textile soaked in salty water. The results obtained using the THz imaging method were compared to the ones obtained using the conventional X-ray method. Overall, the potential of THz transmission measurements was demonstrated and a selected application using THz-based system was presented.

Monitoring of military-designated composites and processing of the images obtained with the use of terahertz radiation

“…Military-designated materials were previously investigated using the THz testing method [6][7][8]. Despite the fact that this method allows detecting the hidden flaws, the results were still beyond expectations.…”

The evolution of the non-destructive defect detection in composites with the use of terahertz radiation

“…Previously, the THz testing method was utilized to examine military-specific materials [5][6][7][8][9]. Although this method has the capability of detecting hidden flaws, the results were unsatisfactory.…”

Terahertz Radiation in Non-Invasive Defect Inspection on Alumina Ceramics

“…THz radiation is nonionizing (low photon energy which for 1 THz is ~4 meV); therefore, it is safe for the human body [9] which increases its competitiveness in relation to other methods, e.g., X-rays. THz radiation has already been successfully used to investigate various military-designated materials such as non-metallic composites [4,6,10], and rocket fuels [7].…”