Papers by Keyword: Ballistic

Abstract: Concrete is a widely used material for construction, playing a crucial role in infrastructural design. Recently, with the increase in threats and protection requirements, developments and investigations are continually needed in concrete for impact-resistant applications. This study investigates the ballistic performance of sixteen concrete formulations subjected to high-velocity impact using a 12.7×99 mm armour-piercing projectile fired from a single-stage gas gun at an impact velocity of 850 m/s. The experimental campaign evaluated depth of penetration (DOP), mass loss, and failure across different concrete formulations under the same test conditions. Concrete types included ordinary concrete (OC), steel- and basalt-fibre-reinforced mixes, ultra-high-performance concrete (UHPC), basalt fibre reinforced concrete (BFRC), rubber aggregate concretes (RSC), and cement-modified variants. Qualitative analysis, high-speed camera sequences, and three-dimensional (3D) scanning were employed to assess the penetration response of each configuration. Results show that UHPC formulations exhibited the best ballistic resistance, with DOP values reduced by nearly 50% compared to ordinary concrete. Steel-fibre-reinforced concretes showed a fibre-dosage-dependent improvement in DOP and material retention, with SF160 emerging as the most balanced solution. In contrast, rubber-modified mixes demonstrated higher DOP but effectively limited surface scabbing. These findings highlight the importance of material composition in optimising ballistic performance and guide the selection of concrete systems for infrastructure protection applications.

Abstract: Post impact microstructural characteristics of 7.62 armour pearcing incendiary bullet was studied on AISI 4340 multilayerd welded joints. The potential application of AISI 4340 steel is found in the construction of combat vehicles using welding process. The welded joints are expected to offer better ballistic resistance like unwelded parent metals in combat vehicles. The traditionally used austenitic stainless steel welding consumables and the transformation effects of the welding process result in inferior ballistic performance of AISI 4340 steel welded joints. Published information revealed that a few attempts were made to successfully resist the bullets at multi layered weld metals by depositing a hard-facing interlayer between traditionally used austenitic stainless steel filler metals and a austenitic stainless steel buttering layer in between the parent metal and the hard – facing interlayer. This paper reports the pre-impact and post-impact microstructural characteristics of multi layered sandwiched joints made of a austenitic stainless steel root, a chromium carbide hard – facing middle layer and a low hydrogen ferritic capping front layer. The effect of the low hydrogen ferritic front layer on the ballistic performance after impact is studied in detail.

Abstract: The combined effect of suction and thermal conductivity on the boundary layer flow of oil–based nanofluid over a porous stretching surface has been investigated. Similarity techniques were employed in transforming the governing partial differential equations into a coupled third order ordinary differential equations. The higher third order ordinary differential equations were then reduced into a system of first order ordinary differential equations and solved numerically using the fourth order Runge-Kutta algorithm with a shooting method. The results were presented in tabular and graphically forms for various controlling parameters. It was found that increasing the thermal conductivities of the base fluid (oil) and nanoparticle size (CuO) of the nanofluid did not affect the velocity boundary layer thickness but depreciates with suction and permeability. The suction parameter and thermal conductivity of the base fluid also made the thermal boundary layer thinner.

Abstract: In this paper we present preliminary results of ballistic testing and thermal measurement of a functional structure consisting of phase change material (PCM) and soft armour layers made of Kevlar. The purpose of this study is to explore the feasibility of combining thermal management with ballistic protection in a single system such that the thermal stress of dismounted combat personnel may be mitigated to an extent while wearing their body armour in hot and humid environments. Under such conditions the breathability of smart textiles will offer little to no benefit. In our study each Kevlar sheet is coated with PCM from Microtek Laboratories Inc. and bonded with normal PVA wood glue. Twenty coated layers were prepared for ballistic testing and compared with twenty pure Kevlar layers as reference. The cooling power of the soft armour insert (SAI) with PCM was measured on a heated sweating manikin. The proof of concept results show that the SAI with PCM only produced a mild cooling effect, which may lower skin temperature and provide a mild cooling sensation for a body region that would otherwise allow limited heat loss, due to the impermeability of the SAI.

Abstract: The Kevlar is an organic high crystalline fiber belonging to the aromatic polyamide family extensively used for its strength. Kevlar fiber posses high cut resistance and flame resistance, hence they have a wide range of application in ballistic and defense ^[2]. This paper investigates how K-149 behaves mechanically under sudden high velocity impact, it also shows which types of Kevlar grade hold the maximum impact stiffness capacity. In addition it also predicts the stress induced on the specimen at the time of impact. The ballistic impact object considered as 9mm standard size bullet used in short gun. The assumed velocity for these cases is 650m/s. The specimens K-149 & k-49 taken to be rectangle with the standard size 50 mm x 50 mm. The computational analysis done on Kevlar 49 & 149 and the results have been compared with the help of the pictorial representation of post processing abaqus results and the best ballistic material can be chosen. This paper also provided the recommended research data to fill the technology gap in defense material science.

Abstract: Laminated glass is widely used as safety material and transparent armor. Its typical structure is sandwich layers of glass sheets and Poly Vinyl Butyral (PVB) film. It is known that the ballistic performance of the laminated glass is highly influenced by its configuration. In this study, the damages from ballistic threats at level 3 according to NIJ standard in laminated glass were investigated. Laminated glass with various configurations was fabricated using rolling and vacuum techniques. The ballistic tests were performed and the resulting radial cracks, which intercept several circumferences on each sheet of glass, were quantified. It was found that the number of crack bifurcation and the configurations of laminated glass were significantly correlated. The tested specimens were also cross-sectional observed using water jet cutting machine so that, their ballistic penetration could be determined. The analysis results provide better understanding of crack evolution, leading to improved new transparent armor system.

Abstract: Composite as main materials for ballistic applications has been developed in order to reduce density which leads to lower fuel consumption and faster mobilization. Composite is required to own high hardness and high impact strength for good ballistic performance. Particulate composites Al-7Si-Mg-Zn reinforced by SiC is designed for ballistic applications due to its light weight and high hardness. Whilst the high hardness showed brittle properties, heat treatment process is applied to this composite to reduce it. This research aims to study the effect of magnesium as alloying element to composite Al-7Si-Mg-Zn reinforced by SiC particulate which applied to precipitation hardening. Composites Al-7Si-Zn-SiC with 2, 4 and 6 wt. % Mg is solution treated at 500 oC for 1 hour, followed by ageing at 200 oC. The characterization was carried out by hardness testing, microstructure observations, SEM and EDX observations, impact testing and fractographic observations. Results showed that Mg does not affect hardness of composite by precipitation hardening. Composite with 2, 4, 6 wt. % Mg had 63.83, 62.27, 62.48 HRB on its peak hardness. Mg did not become precipitate in matrix Al-7Si-Mg-Zn because of its low diffusivity in aluminium. Mg worked as wetting agent that reduces interface tension between aluminium matrix and SiC particles in order for composite to own better interface bonding. Therefore impact testing showed significant increase of impact strength with the increase of Mg content. Composite with 2, 4, 6 wt. % Mg had 2075, 3006, 3257 J/mm2 impact strength respectively

Abstract: This project is about an experimental impact resistance and behaviour of sandwich panel structure, consists of steel plates and kenaf foam. The use of natural fiber reinforcement foam could give a great advantages in weigh reduction which very useful in military mobility and transportability. A standard rifle was used to launch a small bullet (5.56 mm) in constant velocity towards the sandwich panels. The experiments result is based on the depth of the indentation due to the penetration against the armour. The best specimen combining both parameters of study is 20% of kenaf with 45 mm thickness because it can resists the most impact from the bullet. Therefore, it can be concluded that using kenaf to reinforce the polyurethane is success in enhancing its strength and mechanical properties.

Abstract: Fabric materials can be in form of woven, knitted, non-woven and braided structures or a combination of these structures can be used for protective fabric. Properties of fabrics depend on the different types of fibres that constitute the fabric and the geometry of the final structure. This project seeks the development of optimally woven enhanced silk fabric for high performance application that can be potentially beneficial to various engineering fields such as ballistic protection for military, aerospace, automotive, sports and marine engineering industries. Natural enhanced silk will be used as the yarns, rather than the traditionally used synthetically produced aramid material which poses an environmental problem. The tensile strength, tensile modulus and elongation of yarns strength are the main influences on ballistic performance. In addition to the tensile properties of the yarn, fabric weave structure is crucial as propagation of stress waves is affected by the weave structure. Mechanical performance of the woven silk fabric of various designs will be subsequently accessed for their effectiveness based on tensile testing and ballistic testing.

Abstract: Steel wire rope – reinforced aluminium composite - has been developed to improve the ballistic properties and mobility of armour material. Critical to obtaining ballistic resistance is that the materials must be sufficiently hard and strong, especially at the surface where a projectile will first make impact. To obtain this resistance, aluminium alloys can be strengthened by adding Cu and Mg. This research studied the ballistic properties of aluminium composites with varied Cu and Mg content. The matrix used in this study was an Al-7Si master alloy with 0.08-1.03 wt. % Mg and 0.05-3.75 wt. % Cu, both independently and in combination. A high carbon steel wire rope was used as strengthening material. The samples were produced through the squeeze casting process with a pressure of 1 MPa at semi-solid melting temperatures of 590-610 °C. The slab was then rolled for 10 % reduction to increase the hardness. Ballistic testing was performed in accordance with ASTM F1233 by using a 9 mm calibre projectile and 90⁰ direction. Micro structural observation was conducted in the as-cast and ballistic samples, performed with optical microscope and scanning electron microscope (SEM). The results showed that squeeze casting may improve interfacial wettability and reduce void. The increase in Mg resulted in the decline of interfacial voids, but Cu addition tended to increase them. The aluminium armour was able to withstand a 9 mm calibre projectile, although some cracks were visible. The wire rope was not effective in stopping the penetration of a 7.62 mm calibre projectile.