Contact fracturing of rock-like brittle materials indented by rigid cylindrical punches with flat ends is studied. Contrary to the classical shear fracturing mechanism of brittle materials explained in terms of multi-tensile-stressed micro-cracks in materials , a new mechanism dominant in brittle shear fracturing is found, namely, shear stress triggered fracturing orientation existing in nature, and the contact crack initiation angle for such kind rock-like materials is also revealed. This phenomenon is very different from such as Hertzian or Roesler’s  crack generation mechanism, as cracks are directed inwards rather than outwards. The theoretical predictions are validated by our experimental results. This finding testifies that for a rock-like brittle material shear fracturing along its maximum shear stress plane is possible under some special confinement, which has important implications for seismology and rock-mass stability, as well as rock engineering.
- brittle shear fracturing
- rock-like materials
- contact mechanics
- conical crack
Ma, L., Yari, N., & Wiercigroch, M. (2018). Shear stress triggering brittle shear fracturing of rock-like materials. International Journal of Mechanical Sciences, 146-147, 295-302. https://doi.org/10.1016/j.ijmecsci.2018.07.008