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#1 2020-11-08 20:35:48

P929
Member
From: Bogotá, CO
Registered: 2015-07-31
Posts: 110

Modeling interfaces between different materials on a continuous mesh

Hi,

I am performing a simulation of a tunnel excavated in several stages.

In the attached image I show schematically how the construction process is carried out:

Phase 1) the initial stress state is calculated
Phase 2) the excavation of the upper part is carried out
Phase 3) A reinforcement is installed
            3.1) a impermeabilization is installed
            3.2) a concrete layer is installed
            3.3) an additional load is assumed on the top of the concrete
Phase 4) The lower part is excavated
Phase 5) Repeated with the side section

At this time I'm having problems with Phase 3. I can simulate the installation of the concrete and the force above it (Phases 3.2 and 3.3). However, the impermeabilization requires the use of an 'interface' since there is no rigid bond between the concrete and the excavated rock.

In some geotechnical softwares these kind of problems are solve by using some 'interface' elements, which account for the interaction of different materials. They were developed to handle the huge difference in stiffness between soil and concrete, but I don't know if Code_Aster has something similar.

The closes I could imagine was to define a Contact. I tried to use a DEFI_CONTACT, but it shows me the following error:

Contact méthodes maillées.                                                               !
   ! La zone de contact numéro 1 contient 38 noeuds communs aux surfaces maîtres et esclaves. !
   ! Vérifiez la définition de vos surfaces de contact ou bien renseignez un des mots-clés    !
   ! SANS_NOEUD/SANS_GROUP_NO/SANS_MAILLE/SANS_GROUP_MA. 

That would indicate me that the nodes of both the slave and the master are identified as equal, and it is logical because in fact they are the same, as the mesh was created in salome as a continuous

a solution I see would be to create an independent mesh for each excavation/concrete surface, but that would imply the necessity to create many LIASON_MAILLE so that all the meshes behave as a continuous, and this would be really impractical

Is there a way to achieve this in CODE_ASTER?

thx,

Ferney

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