Reference problem
=====================

We read a mesh, we create 3 functions that define:

• for shells

◦ thickness: :math:`\mathit{epais}\mathrm{=}0.001\mathrm{\times }Z`

◦ eccentricity: :math:`\mathit{decal}\mathrm{=}0.002\mathrm{\times }Z`

• for grills

◦ the section: :math:`\mathit{section}\mathrm{=}0.001\mathrm{\times }Z+0.001\mathrm{\times }X\mathrm{\times }Y`

◦ eccentricity: :math:`\mathit{excent}\mathrm{=}0.002\mathrm{\times }(Z+X+Y)`