cohesive (2D)
'''''''''''''

:Sources:

.. collapse:: plate.py (click to expand)

.. literalinclude:: examples/python/solid_mechanics_cohesive_model/cohesive/plate.py
:language: python
:lines: 9-

.. collapse:: material.dat (click to expand)

.. literalinclude:: examples/python/solid_mechanics_cohesive_model/cohesive/material.dat
:language: text

:Location:

``examples/python/solid_mechanics_cohesive_model/`` `cohesive <https://gitlab.com/akantu/akantu/-/blob/master/examples/python/solid_mechanics_cohesive_model/cohesive/>`_


In ``cohesive/plate.py``, an example of extrinsic cohesive elements insertion is shown. This example simulates a plate
with a pre-existing crack pulled. The geometry is depicted in :numref:`fig-ex-cohesive_plate`.

.. _fig-ex-cohesive_plate:
.. figure:: examples/python/solid_mechanics_cohesive_model/cohesive/images/plate.svg
:align: center
:width: 25%

Problem geometry.

The problem is solved statically until the onset of instability and is then solved dynamically with an explicit
integration scheme. This is done by adding a new solver with ``model.initNewSolver()``::

model = aka.SolidMechanicsModelCohesive(mesh)
model.initFull(_analysis_method=aka._static, _is_extrinsic=True)
model.initNewSolver(aka._explicit_lumped_mass)
[....]
model.solveStep("static")
[....]
model.solveStep("explicit_lumped")

The crack opening is displayed in :numref:`fig-ex-cohesive_plate_gif`.

.. _fig-ex-cohesive_plate_gif:
.. figure:: examples/python/solid_mechanics_cohesive_model/cohesive/images/plate.gif
:align: center
:width: 50%

Stresses in the plate.