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In the present paper, the high velocity impact of 9mm soft lead projectile on 10mm and 30mm thick Eglass/ epoxy composites was studied using a 450 kV Flash X-ray radiography (FXR) system. The basic parameters of FXR imaging, such as effect of ratio of target to film (TF) and source to target (ST) distances and X-ray penetration thickness of the composite material were optimized based on clarity and the actual dimensions of the objects. The optimized parameters were used in the FXR imaging of the ballistic event of 9mm soft projectile on E-glass/epoxy composite. The real time deformation patterns of both the projectile and composite target during the ballistic impact were captured and studied at different time intervals. The notable failure modes of the 10mm thick target with time include fibre breakage, bulging on the back side, delamination, recovery of the bulging, reverse bulging and its recovery. However, with increase in thickness of the target to 30mm the only failure mechanism observed is the breaking of fibres. The ballistic impact event was also numerically simulated using commercially available LS-DYNA software. The numerically simulated deformation patterns of the projectile and target at different time intervals are closely matching with the corresponding radiographic images. [ABSTRACT FROM AUTHOR]

In this paper, a modified laminated finite-element model based on subcell of unit cell and CDM material model was developed in nonlinear explicit finite-element code to investigate the dynamic response of 2D triaxial braided composite under ballistic impact of projectile. Six subcells, which were considered as laminate with different stacking sequences using solid elements, were employed to represent one unit cell of triaxial braided composites, therefore, the fiber-laying direction of braiding architecture is reproduced. In the prediction of the subcell model, an approximate round conical deformation area forms in the target and the failure modes are mainly longitudinal and transverse cracking due to tension. Compared with the continuum model, the subcell model is capable of analyzing the energy absorption of fiber in each direction. Although the failure modes are similar for both methods, the subcell model is more effective in prediction of impact wave propagation than the continuum model because it describes the fiber arrangement of triaxial braided composites. The developed subcell model will be an effective tool for the design process of carbon/epoxy composite fan casings. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]