13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- Figure 1. Ballistic set-up. An example of the fragmentation pattern is given in the upper right-hand corner. Rods were loaded by ballistic set-up, which consisted of a gas gun with bore diameter of 19.3 mm, a velocity registration system and a base where the specimen was placed (Fig. 1). The sectional rod was composed of a buffer and the main part covered by an elastic shell. The buffer was used for realization of uniaxial loading produced by a cylindrical projectile of mass 13.9 g accelerated up to the velocities of 6-50 m/s. In order to check influence of loading conditions on fragmentation statistics two types of boundary conditions at the rear end were checked. Rear end of the sample was glued to the steel rod and rear end was free [1]. We found that statistics of fragment distribution does not change significantly so next experiments were carried out with a free rear end of the sample. The mass of the fragments corresponding to the maximum of the probability density function is independent of the projectile energy. To obtain the fragment size distribution, the technique described in the previous experiments [1] was used, which made it possible to get the distribution obeying the scaling law. This experiments are presented in the talk “Scaling Behavior in Quasi Static and Impact Fragmentation of Brittle Materials” by Davydova M. and Uvarov S. at ICF13. The scheme given in Figure 2 illustrates the experimental technique used to measure the distribution of time quantities. Figure 2. Scheme of the experiment. Light source was used for visualizing the cracks in the sample. It is known [3] that cracking of quartz leads to emission of light known as a fractoluminescense or mechanoluminescence. The light intensity was registered by the Photo Multiplayer Tube connected main buffer projectile velocity registration system sample base
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