[Geoqus] Erosion and surface modification with ABAQUS

[Kasper Fischer]

Hi Vincent Godard,

first of all I want to welcome You to the Geoqus User Group. You 
will
find more about Geoqus on
http://www.ruhr-uni-bochum.de/geoqus

I am working with Abaqus for many years. During my Ph.D I have 
worked on
the same topic as You. The interaction of tectonic and surface
processes. It is possible to do the task You want to do, but it is a
little bit tricky. I used a feature of Abaqus to add or delete 
elements
during the calculation. This can be done very easily but one has to
figure out which element is affected. The main disadventage is 
that the
topography is very coarse since the size of the elements can't be 
too
small for a good performance. I have done this with the old 
version of
Abaqus (v. 5.8) and an IDL interface which read in the results of 
the
program to calculate the erosion and sedimentation (Golem by Greg
Tucker) and deciding on the results where to add or remove 
elements. The
current version of Abaqus (v. 6.3) has a scripting interface 
(python)
which might make things easier. If You want I can send You the 
IDL scripts.

A other choice would be to move only the surface nodes of the 
elements.
But I was not sure how this can be done in Abaqus and if it is 
possible
what happens to internal stress and strain values of the affected
element. Maybe somebody else has an idea or done this?

I hope that I could help You and I am looking forward to 
discussing this
topic here.

Kasper Fischer

--
+-----------------------------------------------------------------------+
| Dr. Kasper D. Fischer 
<kasper.fischer at ruhr-uni-bochum.de> |
| Ruhr-Universität Bochum 
       |
| Institut für Geologie, Mineralogie und Geophysik 
       |
| NA 3 / 174                        Tel: +49 234 3227574 
        |
| D-44780 Bochum                    Fax: +49 234 3214181 
        |
| Germany 
www.geophysik.ruhr-uni-bochum.de    |
+-----------------------------------------------------------------------+


Vincent Godard wrote:

>Dear abaqus users,
>
>I am a phd student working on the interactions between tectonics and erosion 
>in orogens. One of my methods of investigation is 2D numerical modeling of 
>the mechanical behaviour of the crust in relation with denudation processes. 
>I am currently using the finite element code ADELI developed by Cherry and 
>Hassani. 
>During my computations with ADELI I am confronted to a significant reduction 
>of the size of the elements close to the surface of my model, due to erosion. 
> ADELI can't perform mesh modification during the computation, so it is an 
>important limitation to the lenght of the simulation.
>To solve this problem I am considering to turn to other finite element 
>softwares which can handle re-meshing during simulations, in particular 
>ABAQUS (my lab already owns a licence), but before doing so I would liketo 
>check if ABAQUS is really appropriate for the kind of modelisation I intend 
>to develop.
>My question concerning ABAQUS is the following: is it possible (and simple) to 
>remove or add material, at regular steps of the simulation, and according to 
>user-defined laws?
>By removing or addition of material I just mean to change arbitrarily the 
>position of the nodes that are defining the topographic surface of the 
>system.
>
>
>Thanks in advance for any advice,
>
>Vincent.
>
>  
>