Definition of CONTACT
====

.. code-block:: text

    ◇ CONTACT = char_contact,

The simple keyword CONTACT allows you to activate the touch-friction resolution or the
taking into account a unilateral connection. contact is a concept derived from the operator
[:ref:`DEFI_CONTACT <U4.44.11>`].

This simple keyword only accepts one concept. So you can't mix in a
same non-linear calculation, the resolution of the contact and the consideration of a connection
one-sided. It is also not possible to mix the different formulations.