Numerical Treatment of Vertex Singularities and Intensity Factors for Mixed Boundary Value Problems for the Laplace Equation in $\mathbb{R}^3 $

Abstract
A numerical method for the computation of the singular behavior of the solution of the Laplace equation is proposed. It is shown that the accuracy of the computed stress intensity factor by the $h,p$, and $h{\text{ - }}p$ version of the finite element method has the same order as the square of the error of the solution measured in the energy norm. Numerical examples are given.