# 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 m rectangle containing two horizontal
cracks, as shown in the following figure:

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:
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:

## Convergence comparisons

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

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

Final meshes for and (hp-FEM):

DOF convergence graphs:

CPU time convergence graphs:

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

The same comparison in terms of CPU time: