  Motivated by some questions arising in the study of quasistatic growth in
brittle fracture, we investigate the asymptotic behavior of the energy of the
solution $u$ of a Neumann problem near a crack in dimension 2. We consider non
smooth cracks $K$ that are merely closed and connected. At any point of density
1/2 in $K$, we show that the blow-up limit of $u$ is the usual "cracktip"
function $\sqrt{r}\sin(\theta/2)$, with a well-defined coefficient (the "stress
intensity factor" or SIF). The method relies on Bonnet's monotonicity formula
\cite{b} together with $\Gamma$-convergence techniques.
