Crack

This example employs adaptive multimesh hp-FEM to solve equations of linear elasticity that we already saw in the tutorial example P01-linear/08-system.

Problem description

The computational domain is a 1.5 \times 0.3 m rectangle containing two horizontal cracks, as shown in the following figure:

Domain.

The cracks have a flat diamond-like shape and their width along with some other parameters can be changed in the mesh file:

a = 0.25   # horizontal size of an eleemnt
b = 0.1    # vertical size of an element
w = 0.001  # width of the cracks

Solved are equations of linear elasticity with the following boundary conditions: u_1 = u_2 = 0 on the left edge, zero external force on the rest of the boundary. The elastic body is loaded with its own weight.

Sample results

Detail of singularity in Von Mises stress at the left end of the left crack:

Solution.

Convergence comparisons

Final meshes for u_1 and u_2 (h-FEM with linear elements):

Solution.
Solution.

Final meshes for u_1 and u_2 (h-FEM with quadratic elements):

Solution.
Solution.

Final meshes for u_1 and u_2 (hp-FEM):

Solution.
Solution.

DOF convergence graphs:

DOF convergence graph.

CPU time convergence graphs:

CPU convergence graph.

Next let us compare the multimesh hp-FEM with the standard (single-mesh) hp-FEM:

DOF convergence graph.

The same comparison in terms of CPU time:

CPU convergence graph.

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