PSI - Issue 6

A. Martemyanov et al. / Procedia Structural Integrity 6 (2017) 336–343 A. Martemyanov et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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It turns out that obtained value is compatible with fracture initiation time received in the loading process by high speed shooting. Macro damage appearance detected through 75 μs , 79 μs , and82 μs . That agrees well with theory.

3.4. Yule Marbledynamic tensile test. Anisotropic case.

Anisotropic properties of marble rock material studied for the case of Yule field, corresponding test results contain in Howe et al. (1974) publication. Samples were plugged in two orthogonal directions. Static tensile strength demonstrate significant difference: material two times stronger in Y-direction than another. Based on given values dynamic characteristics were obtained (see figure 7). Incubation time of Z-oriented samples is 21 μs , same parameter for Y-oriented cylinders takes on value 28 μs .

Fig. 7.Incubation time anisotropy analysis of Yule marble.

As in granite case anisotropic characteristics of marble doesn’t affect on incubation time and caused by static strength.

Conclusions

Study of dynamic strength characteristics with the help of incubation time criterion demonstrates well agreement with experimental results for granite and marble materials. Obtained incubation time may be used for damage accumulation and fracture initiation prediction in given rock medium under complex loadings including impulses. Because of lack of geophysical information and actual experimental conditions received parameters may vary a lot. An assumption about triangle loading function shape in the point of fracture appearance allowed qualitatively to understand that anisotropic strength behavior of granite and marble slightly affect on incubation time value. Further investigation taking into account porous properties, permeability, saturation and temperature will provide deeper understanding of incubation time.

Acknowledgements

The work was supported by the Russian Science Foundation (grant 17-11-01053).

References

Asprone, D., Cadoni, E., Prota, A., Manfredi, G., 2009. Dynamic behavior of a Mediterranean natural stone under tensile loading. International Journal of Rock Mechanics and Mining Sciences 46, 514 – 520. Bragov, A.M., Petrov, Yu.V., Karihaloo, B.L., Konstantinov, A.Yu., Lamzin, D.A., Lomunov, A.K., Smirnov, I.V., 2013. Dynamic strengths and toughness of an ultra-high performance fibre reinforced concrete. Engineering Fracture Mechanics 110, 477 – 488.