PSI - Issue 33

Irina A. Bannikova et al. / Procedia Structural Integrity 33 (2021) 357–364 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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allowed them to make an assumption about the nature of the process of fragile fragmentation as a process of self organized criticality by Naimark and et al. (2017). 5. Conclusion It has been shown experimentally that the fracture of cylindrical specimens made of rock material – quartzite, under dynamic and quasi-static loading is accompanied by fractoluminescence. Cumulative fragment mass distributions and distributions of time intervals between pulses in the signal from the PMT are obtained. The fragment mass distributions have two slopes. They are described by two power laws with an approximation confidence of 0.99. The function describing the fragments mass distribution of sieve with a characteristic size d* > 1.6 mm has a power law degree in modulus greater than 1 and for fragments with d* ≤ 1.6 mm – on the contrary, which corresponds to the processed data by PMT. In the case of dynamic loading, the sample was completely destroyed and the fracture was accompanied by the breakage of the formed fragments. Fracture of specimens under quasi-static loading took place mainly in two stages: accumulation of stresses (the appearance of many main cracks) and subsequent complete failure, as described for other fragile materials in Naimark and et al. (2017). Acknowledgements The work was carried out with the financial support of the RFBR grant (project No. 20-41-596013 r_SEC_Perm Territory). References Astrom, J., Linna R., Timonen J., 2004. Exponential and power-law mass distributions in brittle fragmentation. Physical Review E. 70, 026104(1 7). Bannikova, I., Naimark, O., Uvarov, S., 2016. Transition from multi-center fracture to fragmentation statistics under intensive loading. Procedia Structural Integrity 2, 1944-1950. Davydova, M., Uvarov, S., 2013. Fractal statistics of brittle fragmentation. Fracture and Structural Integrity 24, 60-68. Davydova, M, Uvarov, S., Naimark, O., 2014. Scale invariance during dynamic fragmentation of quartz. Physical Mesomechanics 17, 81-88. Davydova, M., Uvarov, S., Naimark, O., 2016. Space-time scale invariance dynamically fragmented quasi-brittle materials. Physical Mesomechanics 19(1), 86 – 92. Kats, M., Simanovich, I., 1974. Quartz of crystalline rocks (Mineralogical features and density properties). Proceedings 259, Publishing house "Science", Moscow (in Russ.). Katsuragi, H., Sugino D., Honjo H., 2003. Scaling if impact fragmentation near the critical point. Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 68(42), 046105(1 – 6). Katsuragi H., Sugino D., Honjo H., 2004. Crossover of weighted mean fragment mass scaling in two-dimensional brittle fragmentation. Phys. Rev. E. 70(62), 065103(1-4). Meibom, A., Balslev I., 1996. Composite power laws in shock fragmentation. Phys. Rev. Lett. 76(14), 2492 – 2494. Naimark, O., Uvarov, S., Davydova, M., Bannikova, I., 2017. Multiscale statistical laws of dynamic fragmentation. Physical Mesomechanics 20(1), 90-101.