Computational Modeling of Tool-Rock Frictional Contact With Anisotropic Damage

The mechanism of frictional contact is investigated between a blunt tool and quasi-brittle rocks with anisotropic damage. A recently developed anisotropic elasto-plastic-damage model is further validated using experimental results under monotonic and cyclic loadings for rocks and concrete. A finite element model of tool-rock frictional contact is validated by analytical results in the two asymptotic regimes of an elastoplastic rock. The mesh sensitivity is reduced using a fracture energy-based method for anisotropic damage. The tool-rock frictional contact is predominantly controlled by three dimensionless parameters: \(\eta\) $\eta$ , \(\xi\) $\xi$ , and \(\zeta\) $\zeta$ , which characterize elastoplasticity, brittleness, and anisotropic damage, respectively. The newly introduced damage coefficient \(\zeta\) $\zeta$ controls the ratio of damage in different directions. As the elastoplastic parameter \(\eta\) $\eta$ increases with more plastic deformation, the dimensionless average contact stress \({\widetilde{\Pi }}\) $\tilde{\mathrm{\Pi }}$ increases and then slightly varies before stabilizing. As the brittleness number \(\xi\) $\xi$ increases in a more brittle mode, the contact stress \({\widetilde{\Pi }}\) $\tilde{\mathrm{\Pi }}$ generally decreases. When the damage coefficient \(\zeta\) $\zeta$ decreases from isotropic to anisotropic damage, the contact stress \({\widetilde{\Pi }}\) $\tilde{\mathrm{\Pi }}$ generally increases. The magnitudes of the average contact stress in numerical modeling are closer to experimental results when considering anisotropic damage.