Investigation of Stab Protection Properties of Aramid Fibre-Reinforced 3D Printed Elements

Abstract

A stab resistant vest is a reinforced piece of body armour designed to resist knife or needle attacks of different energy levels specifically to the upper part of the body (chest and abdomen) to save lives. The majority of armours limit several comfort parameters, such as free locomotion, respiration, flexibility and light weight, which determine efficient use by wearers and their willingness to wear. Currently available armours are usually made of a single plate, and although often segmentation is used with just a few but still quite large pieces, the materials are compact and bulky to wear. In this study, stab protective armor elements (scale-like elements) of 3 mm thickness and 50 mm diameter were designed, produced (3D printed) and tested for performance. Aramid fibre was used for its strength, durability and process ability to develop protection elements at unidirectional and multidirectional filling angles during 3D printing. The specimens were tested according to VPAM KDIW 2004. The specimens designed and developed with multidirectional filling angles of aramid resist the puncturing energy level K1 (25 J) with a penetration depth less than the maximum allowed for the K1 energy level by VPAM. These specimens showed a high protection level of relative small thickness (3 mm) and light weight (6.57 grams for the estimated area A ≈ 1963.5 mm2) as compared to the currently certified armors for K1 (for example, the aluminum mass is 13.33 grams for 2 mm thickness and 50 mm diameter).