Low and high velocity impact on Inconel 718 casting plates: ballistic limit and numerical correlation

The study of materials under dynamic external loads requires the knowledge of their dynamic response or else their deformation behavior under quickly varying loads (Impact dynamics, Wiley, New York, 1976; High velocity impact dynamics, Wiley, New York, 1990). When the intensity and the application velocity of the loads become higher, the inertial loads may not be considered negligible. If the loads generate stresses higher than the yield limit, then elastic and plastic waves cross the material at different velocities. The analysis of plastic wave propagation needs an analytical description of the material behavior in relation to the strain rate, in order to obtain a dynamic constitutive equation. The conventional stress–strain material curve has to be modified by this equation. Nevertheless, the mentioned equation is generally unknown. The experimental study presented in this paper has two objectives: (i) to determine the structure response under highly variable loads and during a penetration event, (ii) to obtain a dynamic characterization for the material. An experimental ballistic limit curve for high velocity impact is also provided by an empirical correlation derived from experimental results.