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


Geometry
---------

It is a material point, treated by SIMU_POINT_MATen 3D or in D_ PLANselon modeling or with a single element and STAT_NON_LINEpour COQUE_SOLIDE.


Material properties
----------------------

The material obeys the law of fragile elastic behavior ENDO_LOCA_EXP. The macroscopic data correspond to:


.. csv-table::

    ":math:`E=34129\text{MPa}` ", "Young's module"
    ":math:`\nu =0.2` ", "Poisson's ratio"
    ":math:`{G}_{f}=0.142{\text{N/mm}}^{2}` ", "Cracking energy"
    ":math:`p=2` ", "Shape parameter"
    ":math:`{f}_{t}=3.024\text{MPa}` ", "Traction limit"
    ":math:`{f}_{c}=40\text{MPa}` ", "Compression limit"
    "", ""
    ":math:`{L}_{f}=200\text{mm}` ", "Inter-crack distance"


The internal parameters of the model are calculated by the macro command DEFI_MATER_GC.


Boundary conditions and loads
-------------------------------------

It is a request at a material point (SIMU_POINT_MAT). All deformation components are imposed; they are all zero except for EPXX. We start by imposing a uniaxial tensile deformation and then unloading until a compression deformation is imposed in order to verify the effect of the restoration of stiffness under compression.


Initial conditions
--------------------

None.