Johnson-Cook high strain-rate constitutive and failure modeling for 7B52 laminated plate and its ballistic performance under blunt projectile impact

The finite element method based on the Johnson-Cook (J-C) model has become an important numerical approach for investigating the ballistic performance of materials. To reveal the dynamic mechanical response and failure mechanisms of 7B52 aluminum alloy laminated plates under blunt projectile impact, quasi-static tensile tests at room temperature, split Hopkinson pressure bar (SHPB) dynamic compression tests, and high-temperature compression tests were conducted. The J-C constitutive parameters and damage parameters of the 7A62, 7A01, and 7A52 aluminum alloy constituents were then calibrated. A three-dimensional finite element model of blunt projectile penetration into the laminated target was established, and its reliability was validated by ballistic experiments using a single-stage light-gas gun. The results show that all three aluminum alloy constituents exhibit pronounced strain-rate hardening and thermal softening effects. The calibrated parameters can effectively describe the elastoplastic deformation and damage evolution of 7B52 laminated plate under high-strain-rate loading. The projectile residual velocities predicted by the finite element simulations agree well with the experimental results, with a prediction error of less than 6.2%. The model also accurately reproduces the perforation morphology and local damage characteristics of the target. Under high-velocity impact by a hard blunt projectile, the dominant failure modes of the laminated plate target are shear plugging and plastic deformation. Owing to the high metallurgical bonding strength between the constituent layers, no obvious deformation incompatibility or interfacial delamination is observed after impact. This study provides experimental support and numerical guidance for dynamic constitutive modeling, ballistic performance evaluation, and lightweight armor design of aluminum alloy laminated plates.