PSI - Issue 40

A.M. Ignatova et al. / Procedia Structural Integrity 40 (2022) 185–193 Ignatova A.M. at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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3. Results and their discussion Fig. 3 shows frames from video recordings corresponding to various collision parameters. When processing the obtained video recordings, the following phenomena were found that make it difficult to analyze them: - rotation of rupture fragments in the process of fragmentation of the fragment cloud; - flickering of rupture fragments during rotation (due to the properties of the material itself); - secondary acceleration of fragments in a stream of compressed air that accelerated the impactor. To avoid the influence of these factors, data on zero velocities and data on sharp speed jumps were excluded from the results of frame-by-frame analysis, assuming that secondary phenomena cause them. Fig. 4 demonstrates the diagrams characterizing the change in the velocity of the fragments after collision during the first 4 microseconds, and Fig. 5 shows the averaged dependencies based on the data from the diagrams. a b

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Fig. 3. Frames from video recordings of fragmentation of targets made from potassium fluorophlogopite at impact with a steel ball: (a) at a speed of 230 m/s, collision angle of 90°; (b) at a speed of 120 m/s, collision angle of 90°; (c) impact at a speed of 230 m/s, collision angle of 30°; (d) impact at a speed of 120 m/s, collision angle of 30°