Ballistic Limit of High-Strength Steel and Al7075-T6 Multi-Layered Plates Under 7.62-mm Armour Piercing Projectile Impact

Abstract

This paper presents the computational-based ballistic limit of laminated metal panels comprised of high strength steel and aluminium alloy Al7075-T6 plate at different thickness combinations to necessitate the weight reduction of existing armour steel plate. The numerical models of monolithic configuration, double-layered configuration and triple-layered configuration were developed using a commercial explicit finite element code and were impacted by 7.62 mm armour piercing projectile at velocity range of 900 to 950 m/s. The ballistic performance of each configuration plate in terms of ballistic limit velocity, penetration process and permanent deformation was quantified and considered. It was found that the monolithic panel of high-strength steel has the best ballistic performance among all panels, yet it has not caused any weight reduction in existing armour plate. As the weight reduction was increased from 20-30%, the double-layered configuration panels became less resistance to ballistic impact where only at 20% and 23.2% of weight reduction panel could stop the 950m/s projectile. The triple-layered configuration panels with similar areal density performed much better where all panels subjected to 20-30% weight reductions successfully stopped the 950 m/s projectile. Thus, triple-layered configurations are interesting option in designing a protective structure without sacrificing the performance in achieving weight reduction. Keywords Ballistic impact; ballistic limit; double-layered plate; numerical simulation; triple-layered plate N.A. Rahman et al. / Ballistic Limit of High-Strength Steel and Al7075-T6 Multi-Layered Plates Under 7.62-mm Armour Piercing…

Experimental and Numerical Investigation on the Layering Configuration Effect to the Laminated Aluminium/Steel Panel Subjected to High Speed Impact Test

“…A constant mesh size of 0.5 mm was selected to finely resolve each problem and make the through thickness elements for the penetration process to be 50 elements. This size was found to adequately produce good results based on previous work by Rahman et al (2016) [15]. The plates were modelled using node-to-node connectivity using pure langrage algorithm with implementation of geometric erosion strain to avoid failure.…”

“…All panels have same total thickness of 25 mm. The important factor in the sample size is its thickness because the selected thickness of 25 mm is the standard thickness of existing armour panel [15]. Each layer thickness was set accordingly to the 25% weight reduction of original armour panel to ensure the body maintaining on the ground during extreme conditions such as blasting and explosion.…”

“…Node-to-node connectivity was applied using pure langrage algorithm with implementation of geometric erosion. This technique was able to remove the elements experiencing large distortion and, consequently, simulation failure can be avoided [10,15]. Developing glue or bonding model in finite element modelling is another issue occurred frequently in obtaining accurate result [16].…”

Brazed Joint Interface Bonding Strength of AR500 Steel and AA7075 Aluminium Alloy

“…However, the high cost of aluminium compared to steel restricts its usage in automobile parts. As a result, aluminium is more economical when it can be used in hybrid structures with steel [4][5][6][7]. There has been considerable research on the dissimilar metal joining of aluminium alloys and steel using several joining techniques, such as spot welding [8], laser welding [9], brazing [10][11][12], and friction stir welding [13].…”

Energy absorption capability and deformation of laminated panels for armoured vehicle materials

“…It has been observed that aluminium has some weaknesses compared to high-strength steel when dealing with structural impact. Since aluminium plates have poor ballistic performance, they are often utilised in multi-layered or spaced structures in combination with other materials [6,7].…”