FSI issue in abaqus co-simulation: misaligned nodes

Hi everyone,

 I am performing FSI simulation under abaqus.

The simulation consists in a porous solid (elastic isotrope and homogeneous under Abaqus/explicit) filled by a non newtonian (viscous fluid under Abaqus/CFD). The whole is contained in a cubic shell in order to apply proper boundary condition.

The cube is pinned on one face and undergoes a compression displacement on the opposite face. I have defined an interaction condition between the solid surface and the fluid model surface so Abaqus can exchange information during Explicit and CFD simulation.

The simulation runs well until I diminish the element's size, then the simulation doesn't start and give me the following error message:

***WARNING: When performing co-simulation mapping from the partner code (the
            source) to /Explicit (the target): search failed for the following
            target elements:
          
          
          These nodes are written to the output database (odb) in nodeset
          COSIMULATION_ENGINE_SEARCH_MISALIGNED_NODES

 I looked into the Abaqus documentation which gives the advise to put a skin on the solid geomtry in order to paste the mesh on the 2nd model geometry. This works only for a co-simulation between Abaqus/Standard and Explicit, but the skin option does't seem to exist for the fluid model.

I also tried to define exactly the same size of element in both solid and fluid model, but I still have the same error message. Also the explicit simulation performed alone works fine, so seems to indicate that the problems remains in the interface between the solid and the fluid.

Have you guys encountered the same kind of problem or could you give me some advice in order to solve this problem? I would very much appreciate.

Thanks in advance.

Romain