Predictive models and experiments for high-velocity and high-temperature impacts in Inconel-alloy panels

The behavior of Inconel 718 and 617 panels on the high-speed impact perforation mode at elevated temperatures and ballistic impact limit is here investigated using experimental and numerical methods. Impact tests have been performed using a custom-made two-stage light-gas gun rig, with the specimens being subjected to high temperatures (up to 1007 °C). The panels have been impacted using spherical projectiles with velocities ranging from 0.5 to 2.2 km/s. During the experiments the failure of the targets has been evaluated by varying parameters like the projectile diameter, its density and the oblique impact angle. An analytical model to estimate the residual velocity and the ballistic limit equations has been established. Finite element models (FEM) combined with phenomenological analytical models have been also developed to validate the predictive results obtained by the analytical model. The simulations from the FEM and the analytical models provide a good match with the experimental data. For the two typical cases (normal impact and oblique impact), the shapes and sizes of the damaged holes have been also well predicted by the numerical model. Equivalent diameters of the impacts have also been identified as functions of the velocity, diameter of the projectile and panel thickness.