Theory of unconventional singularities of frictional shear cracks

Crack-like objects that propagate along frictional interfaces, i.e. shear cracks, play a major role in broad range of phenomena. Such cracks are commonly assumed to feature the universal square root near-edge singularity ideal as predicted by Linear Elastic Fracture Mechanics. Here we show this is not generic case due intrinsic dependence strength on slip rate, even if bodies forming interface identical and predominantly linear elastic. Instead, unconventional singularities characterized order ξ differs from conventional − 1 2 one. It shown depends friction law, propagation speed symmetry mode loading. We discuss general structure theory singularities, with their implications for energy balance dynamics cracks. Finally, present explicit calculations associated fields viscous-friction – which may emerge perturbative approximation nonlinear laws or its own both in-plane (mode-II) anti-plane (mode-III) loadings.