Reference problem
====

The behavior of a multi-fissured plate under tension is studied. In order not to mesh the cracks, the X- FEM method is used.

We consider an infinite plate in tension, comprising 2 cracks of length :math:`\mathrm{2a}` (see).


.. image:: images/100000000000027B000001F881101B1229EFE579.jpg
    :width: 3.3071in
    :height: 2.6256in


.. _RefImage_100000000000027B000001F881101B1229EFE579.jpg:

Figure 1-1: geometry of the problem

We propose to check the charts provided by the "Handbook of stress-intensity factors" from :math:`G`. Sih. The stress intensity factor :math:`{K}_{I}` at point :math:`A` is given by the following formula:

:math:`{K}_{I}^{A}\mathrm{=}F(\frac{2a}{r},\frac{e}{b})\sigma \sqrt{\pi a}` where :math:`F(\frac{2a}{r},\frac{e}{b})` is given by the graph of the.