E modeling
==============

Characteristics of the models
----------------------------------

The plate is not modelled since it is subject to rigid body movement. The spring mat is modeled by interface elements (3D_ INTERFACE_S). The interface behavior relationship is CZM_ELAS_MIX in which the tensile stiffness density is zero (detachment without stiffness) and the compression stiffness density is simply equal to :math:`k`, without other treatments. A tangential stiffness (equal to :math:`k`) is also added to avoid any transverse movement.


Characteristics of the mesh
----------------------------

The spring mattress is cut into 20 x 1 interface elements.


Tested sizes and results
------------------------------

The results of*Code_Aster* are compared with the **continuous** reference solution and high accuracy.


.. csv-table::

    "**Nature of results**", ":math:`{U}_{A}` "," :math:`{U}_{B}`"
    "Instant Continuous Solution 1"," :math:`\frac{-4}{1125}` "," :math:`\frac{4}{3375}`"
    "Instant Continuous Solution 2"," :math:`\frac{-4}{1125}+\frac{5}{1000}` "," :math:`\frac{4}{3375}+\frac{5}{1000}`"
    "Tolerance", ":math:`2.0E-07` "," :math:`2.0E-07`"