Energy Absorption and Limit Velocity of Epoxy Composites Incorporated with Fique Fabric as Ballistic Armor-A Brief Report.

Michelle Oliveira,Fernanda Luz,Lucio Nascimento,Henry Lopera,Fabio Garcia Filho,Sergio Monteiro

doi:10.3390/polym13162727

Michelle Oliveira, Fernanda Luz + Show 4 more

Open Access

https://doi.org/10.3390/polym13162727

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Abstract

Polymer composites reinforced with natural fabric have recently been investigated as possible ballistic armor for personal protection against different levels of ammunition. In particular, fabric made of fique fibers, which is extracted from the leaves of the Furcraea andina, was applied as reinforcement for polymer composites used in a multilayered armor system (MAS). The superior performance of the fique fabric composites as a second MAS layer motivated this brief report on the determination of the absorbed energy and capability to limit velocity in the stand-alone ballistic tests. The single plates of epoxy composites, which were reinforced with up to 50 vol% of fique fabric, were ballistic tested as targets against 7.62 mm high-speed, ~840 m/s, impact ammunition for the first time. The results were statistically analyzed by the Weibull method and ANOVA. The absorbed energies of the 200–219 J and limit velocities of 202–211 m/s were found statistically similar to the epoxy composites reinforced with the fique fabric from 15 to 50 vol%. Predominantly, these findings are better than those reported for the plain epoxy and aramid fabric (KevlarTM) used as stand-alone plates with the same thickness. Macrocracks in the 15 and 30 vol% fique fabric composites compromise their application as armor plates. The delamination rupture mechanism was revealed by scanning electron microscopy. By contrast, the integrity was maintained in the 40 and 50 vol% composites, ensuring superior ballistic protection compared to the use of KevlarTM.

Highlights

Synthetic laminates made of ultra-high-molecular-weight polyethylene (UHMWPE), under the trademarks of DyneemaTM and SpectraTM, as well as aramid fiber, supplied as KevlarTM and TwaronTM, have been the most common materials used worldwide for bulletproof vests [1,2,3]
Pereira et al [17] found that polyester composites reinforced with 10, 20 and 30 vol% fique fabric displayed a backface signature (BFS) of 16–20 mm, which is much less than the limit value of 44 mm imposed by the standard as a lethal trauma [16]
Oliveira et al [18] reported that a 150 × 150 mm2 ballistic plate with a 10 mm of thickness made of epoxy composite, incorporated with 40 vol% of fique fabric, would cost USD 3.67, whereas the same plate made of KevlarTM would cost USD 20.61. These findings present the same plate made of KevlarTM as more than five times the price of the fique fabric composite

Summary

Introduction

Synthetic laminates made of ultra-high-molecular-weight polyethylene (UHMWPE), under the trademarks of DyneemaTM and SpectraTM, as well as aramid fiber, supplied as KevlarTM and TwaronTM, have been the most common materials used worldwide for bulletproof vests [1,2,3]. Pereira et al [17] found that polyester composites reinforced with 10, 20 and 30 vol% fique fabric displayed a BFS of 16–20 mm, which is much less than the limit value of 44 mm imposed by the standard as a lethal trauma [16] These BFS values are better than the average 23 mm which has been reported for the MAS with KevlarTM as the second layer with the same thickness [11]. In terms of ballistic protection, the limit velocity might indicate the level of ammunition against which the plate could still be used alone as an effective armor This brief report complements previous BFS results from the ballistic tests of fique fabric reinforced epoxy composites as an MAS second layer [18]. The absorbed energy and limit velocity in stand-alone targets against the threat of 7.62 mm ammunition have been measured

Materials

Ballistic Parameters

Weibull Statistical Analysis

Stand-Alone Ballistic Tests

Composites Integrity and Failure Analyses

Summary and Conclusions