Ballistic Impacts with Bullet Splash-Load History Estimation for .308 Bullets vs. Hard Steel Targets

The study focuses on testing a simplified way of estimating the resultant force due to ballistic impacts resulting in a full fragmentation of the impactor with no penetration of the target. The method is intended to be useful for the parsimonious structural assessment of military aircrafts with integrated ballistic protection systems by means of large scale explicit finite element simulations. The research investigates the effectiveness of the method in allowing the prediction of the fields of plastic deformation collected by hard steel plates impacted by a wide range of semi-jacketed, monolithic, and full metal jacket .308 Winchester rifle bullets. The outcomes show the effectiveness of the method being strictly related to the full compliance of the considered cases with the bullet-splash hypotheses. The study therefore suggests the application of the load history approach only after careful experimental investigations on the specific impactor-target interactions.

A Numerical Modelling Framework for Investigating the Ballistic Performance of Bio-Inspired Body Armours

Biological structures possess excellent damage tolerance, which makes them attractive for ballistic protection applications. This paper develops a finite element modelling framework to investigate the performance of several biological structures that are most relevant for ballistic protection, including nacre, conch, fish scales, and crustacean exoskeleton. Finite element simulations were conducted to determine the geometric parameters of the bio-inspired structures that can survive projectile impact. The performances of the bio-inspired panels were benchmarked against a monolithic panel with the same 4.5 mm overall thickness and projectile impact condition. It was found that the biomimetic panels that were considered possessed better multi-hit resistant capabilities compared to the selected monolithic panel. Certain configurations arrested a fragment simulating projectile with an initial impact velocity of 500 m/s, which was similar to the performance of the monolithic panel.

A fit and function analysis of the UK OSPREY body armour system for female users

INTRODUCTION

OSPREY personal armour has been issued to UK forces since 2005. From 2015, the VIRTUS personal armour and load carriage system have been progressively replacing OSPREY. In 2016, the ban on women in ground close combat roles throughout the UK's Armed Forces was lifted. In anticipation of this, work has been ongoing to prepare future ballistic protection programmes for a potential increase in the number of female users.

METHOD

A human factors questionnaire was provided to 150 female users of OSPREY body armour to complete while on combat operations in Afghanistan. The questionnaire asked the users to rate the comfort of their OSPREY body armour along with their ability to carry out basic tasks. Other background data such as size of body armour worn and bra size were also collected for the analysis.

RESULTS

The female participants reported various types of discomfort when wearing their OSPREY body armour, with 135 instances of discomfort experienced in the hip region, for example. Challenges were reported in the ability to carry out basic movements, with the tasks rated on a Likert scale as difficult or very difficult by between 29% and 59% of participants. In addition, a restriction in ability to access personal equipment worn on the person (including pouches, trouser pockets) was commented on by 39% of participants.

CONCLUSIONS

Female users reported challenges relating to the fit and function of OSPREY body armour. The VIRTUS body armour system for UK Armed Forces Personnel has already addressed many of the reported issues with OSPREY. Further optimisation for VIRTUS with regard to female users is planned and includes sizing of ballistic hard plates.

Multi-Criterial Analysis Tool to Design a Hybrid Ballistic Plate

The presented research focuses on the concept of an advanced ballistic personal protection design, taking into account safety as well as performance requirements. The application of the multi-criterial analysis (MCA) allows for a comprehensive comparison of all the properties of materials and to select the optimal personal ballistic protection system, considering their mechanical and ballistic properties. The newly developed hybrid ballistic composites, consisting of two or three various components (variations of ballistic and/or non-ballistic textiles; hybrid ballistic plates—HBP), were evaluated via a multi-criterial analysis that considered a wide range of properties, describing behavior and safety usage, as well as the economical aspect of their fabrication.

A Facile Synthesis Route of Hybrid Polyurea-Polyurethane-MWCNTs Nanocomposite Coatings for Ballistic Protection and Experimental Testing in Dynamic Regime

This study describes a simple, practical, inexpensive, improved, and efficient novel method for obtaining polyurea-polyurethane-multiwall carbon nanotubes (MWCNTs) nanocomposites with enhanced mechanical properties, and their experimental testing in a dynamic regime. SEM and micro-CT investigations validated the homogeneity of the nanocomposite films and uniform dispersion of the nanofiller inside the polymeric matrix. The experimental measurements (TGA, DSC, DMA, and tensile tests) revealed improved thermal and mechanical properties of these new materials. To demonstrate that these nanocomposites are suitable for ballistic protection, impact tests were performed on aluminum plates coated with the polyurea-polyurethane MWCNTs nanocomposites, using a Hopkinson bar set-up. The experimental testing in the dynamic regime of the polyurea- polyurethane-coated aluminum plates confirmed that the nanocomposite layers allow the metal plate to maintain its integrity at a maximum force value that is almost 200% higher than for the uncoated metallic specimens.

Design and Evaluation of Hybrid Composite Plates for Ballistic Protection: Experimental and Numerical Investigations

In this paper, hybrid composite plates for ballistic protection were investigated experimentally and numerically, with a target to reduce the weight of currently used body armor inserts and, at the same time, satisfy the requirements of the National Institute of Justice’s (NIJ) ballistic protection standards. The current study has three phases to improve the ballistic plate’s energy absorption capability. The first phase is devoted to studying the effect of the material types, including three different fibers: carbon fiber, date palm fiber, and Kevlar fiber. The second phase is dedicated to studying the effect of hybridization within layers. The two previous phases’ results were analyzed to optimize the material based on the hybrid composite ballistic plate’s maximum energy absorption capability. The commercial finite element software package LS-DYNA was employed for numerical modeling and simulation. The hybrid composite ballistic plate could absorb more impact energy than the non-hybrid Kevlar plate with the same area density from the numerical simulation results. This study provides lighter-weight ballistic inserts with a high protection level, making movement easier for the wearer. The numerical results were verified by comparing results of a plate made of 40 layers of Kevlar with an actual ballistic test. The results indicated that the simulation results were conservative compared to the ballistic test.