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This paper discusses on the penetration of high velocity projectiles through aluminium–polyurea composite layered plate systems. An analytical model has been proposed to predict the residual velocity of aluminium–polyurea composite plates, and validated with both experimental and numerical investigations. Full metal jacket (FMJ) projectiles (5.56 mm × 45 mm), corresponding to NATO standard SS109, were fired at the aluminium–polyurea composite layered plate systems from a distance of 10.0 m at a fixed velocity of 945 m/s. Four different composite plate configurations were used with thicknesses varying from 16 to 34 mm. Each configuration consisted of six specimens. Residual velocities for each individual test were recorded. Numerical simulations of the penetration process have been performed using advanced finite element code LS-DYNA®. The well-established Johnson–Cook and Mooney–Rivlin material models were used to represent the stress–strain behaviour of aluminium and polyurea in the numerical analysis. The analytical and numerical models provided good approximations for the residual velocities measured during the experimental tests. Polyurea layers contributed positively towards the reduction of residual velocity of the projectile in composite plate systems. In addition, ballistic limit curves for different composite systems have been established based on the validated models. As the results showed that polyurea contributes positively towards the reduction of residual velocity of projectiles, the findings of this study can be effectively used for the similar applications in future armour industry. [ABSTRACT FROM AUTHOR]

Highlights: [•] Aluminium–polyurea composites plates were subjected to low velocity impacts. [•] Projectile impacts were simulated using advanced finite element code LS-DYNA. [•] Out-of-plane deformations were measured and compared with numerical predictions. [•] Polyurea showed good ability in reducing permanent plastic deformation. [•] Composite plate show better ability in absorbing impact energy. [Copyright &y& Elsevier]

A strain rate dependent constitutive material model to predict the high strain rate behaviour of polyurea has been proposed. The well-known nine parameter Mooney–Rivlin constitutive material model was considered as the base model in deriving the rate dependent material model. A rate dependent term was introduced into the original Mooney–Rivlin model and was validated using high strain material data for polyurea. Due to its simplified formation and extensive use in finite element codes such as LS-DYNA® and ANSYS®, improvement of the original model shows a higher significance in terms of constitutive model development for hyper-elastic materials. High strain rate tensile tests program has been conducted to obtained the material model parameters. Experimental and model prediction for both stress–strain and energy behaviour of the material indicates close agreement. Stress–strain non-linearity and high strain rate sensitivity of polyurea is also highlighted in this paper. [ABSTRACT FROM AUTHOR]

Highlights: [•] Penetration of projectiles through polyurea coated aluminium plates were studied. [•] Residual velocities of the projectiles through composite plates were measured. [•] Failure mechanisms of different plate configurations are presented. [•] Polyurea coating indicated good ability in reducing the residual velocity. [•] Ability of polyurea coating as a protective material has been highlighted. [ABSTRACT FROM AUTHOR]