Development of an automated assessment technology for detecting damage in body armour

Abstract

Hard ballistic body armour plates are designed to withstand the impact of a bullet and protect the wearer, if this happens the armour is clearly damaged and so is retired from service. Mishandling, however, such as dropping the armour, may cause minor and difficult to detect damage which compromises the effectiveness of the plate. Current methods of inspection involve shipping the plates to a central location, performing a thorough inspection and returning them to service if uncompromised; this is costly and requires redundancy of equipment for when not in service. Acousto-Ultrasonics is a method of structural health monitoring in which ultrasonic waves are excited in a structure by a transducer and receivers record the response, any deviation from a baseline measurement give an indication of damage within the structure. Within this paper the development and testing of a novel handheld prototype device is presented, which gives a simple yes/no answer to if there is damage on the plate. This inspection is quick and easy to perform by unskilled personnel. Low profile sensors have been utilised combined with a novel flexible circuitry with built in memory, which does not compromise the effectiveness of the armour.

Development of a Novel Flight Time Matrix for Nondestructive Evaluation Using Acousto-Ultrasonics -A Case Study of Multilayered Armor Plates Damage Detection

“…Issues involved in the integrity and reliability evaluation of these plates include defects, delamination, cracks, and other structural integrity that make an armor plate to be defective. Occurrence of defective plate can be resulted in a number of circumferences such as from manufacturing processes, through rough service, and mishandling [1,2]. The existence of defects will lessen the ability of ballistic protection that armor plates may become compromised.…”

“…It can be seen that AE and ultrasonics method fit for all the categories. Over the years, AE and ultrasonics have been applied extensively and many successful achievements been reported [2,11,16]. However, waveform evaluation was employed in most AE related work, and ultrasonics studies were more involved in single layer materials.…”

Contribution of Lamb wave modes in the formation of higher order modes cluster (HOMC) guided waves

“…These modes are relatively easy to generate individually because of their significantly different phase velocities in this region. The region marked (2) in Figure 1(a) includes the higher order modes at higher frequency-thickness values (3MHz-mm to 10MHz-mm) which result in higher resolution compared to fundamental modes A 0 and S 0 . Working with higher order modes is difficult due to dispersion effects and presence of multiple modes.…”

“…Most conventional ultrasonic testing techniques utilized for testing plate-like structures take advantage of Lamb waves in one way or the other. [1][2][3][4] Lamb waves are guided waves that follow the boundaries of plate-like structures and can travel long distances without noticeable damping. 5 Lamb waves are dispersive, which means that their velocity is a function of frequency.…”