Effectiveness of prediction method of indentation size formed by high-velocity impingement of a solid sphere

The fan blades and turbine blades in a jet engine are severely damaged by high-velocity impingements of various foreign objects. In our recent study, a prediction method of indentation size (PMIS) formed by the high-velocity impingement of a solid sphere has been established based on an expanding cavity model combined with the Johnson–Cook (JC) flow stress model and energy conservation in the impingement process. The indentation size formed by a high-velocity impingement up to 400 m/s can be estimated using the PMIS with appropriate material constants on a target material on the JC model, which is called JC parameters. In this study, to demonstrate the effectiveness of the PMIS, a high-velocity impingement test of a solid sphere was conducted using three metallic materials: pure copper (ASTM-C10200), austenitic stainless steel (AISI-304), low-carbon steel (AISI-1015). A high-carbon chromium steel ball with a diameter of 4.5 mm was impinged onto these three target materials at several impingement velocities from 50 to 350 m/s. The JC parameters on these three materials were identified via a quasi-static tensile test and a high-speed tensile test under a strain rate of approximately 100 s⁻¹. Results show that the depths of indentation estimated by the PMIS agreed well with the experimental results irrespective of the target material. Consequently, it was demonstrated that the PMIS can effectively estimate the indentation depth formed by the high-velocity impingement of a solid sphere up to 350 m/s.