V. A. Kondrat'ev, V. A. Nikishkin

On the Asymptotics of Solutions of Elliptic Equations in a
Neighborhood of a Crack with Nonsmooth Front

abstract:
Two terms of asymptotics near crack are obtained for solutions of the Dirichlet boundary value problem for second-order elliptic equations in divergent form. The front of a crack is from $C^{1+s}$ and the coefficients of the equations belong to $C^{s}$ $(0.5<s<1).$