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

191 7

2 1 k V k t    ,

(5)

where the first factor k 1 can be expressed using the kinetic energy of the fragment ( E k ) in the initial moment multiplied by the scale factor ( M ), which according to the experiment is 20 for frontal impact and 2 for the impact at an angle of 30 o , and the second coefficient k 2 can be expressed using the collision angle, and meets the obtained curves of 0.3 for impact at an angle of 90 o and 0.4 for impact at an angle of 30 o . The equations of the function can be written as:

2 k

k V ME t   

(6)

The established values of the coefficients are reliable for the material considered in the experiment and cannot be extrapolated to other materials without preliminary analysis.

Fig. 5. Averaged dependences of change in the velocity of rupture fragments of a target made from potassium fluorophlogopite at impact with a steel ball: 1 – at a speed of 230 m/s, collision angle of 90°; 2 – at a speed of 120 m/s, collision angle of 90°; 3 – impact at a speed of 230 m/s, collision angle of 30°; 4 – impact at a speed of 120 m/s, collision angle of 30°

Table 1. The particle-size distribution of the rupture fragments of each of the experiments Impactor velocity, m/s Collision angle, ͦ

Average fragment size, mm

Minimum fragment size, mm

Maximum fragment size, mm

The kinetic energy of fragments, J

230 120 230 120

90 90 30 30

3.47 2.36 3.37 3.99

2.37 1.80 2.75 3.08

5.09 3.03 4.31 5.15

27-78 24-45 52-81 17-24