2. Reference solution

There is no reference solution for this problem. Non-regression tests are therefore carried out. We check that the \(\mathrm{XFEM}\) tests give the same results as their \(\mathrm{FEM}\) counterparts. As such, modeling \(D\) is a reference for models \(E\) to \(G\), modeling \(A\) is a reference for modeling \(H\) and modeling \(C\) is a reference for models \(I\) and \(J\).