Submodel analysis with force boundary conditions

i managed to do a submodel analysis by mapping the displacements from global to submodel. i want to do it now by mapping of force boundary conditions from that submodel. my steps were as following:

-doing first submodel analysis with displacements mapping as mentioned
-using .frd file of that submodel analysis with RF stored to do second submodel analysis
-here comes the mistake i guess by trying to map RF from .frd file to the boundary nodes.




this is how my inp file looks like. boundary_nodes is the nset of the submodel containing the nodes on the boundary. the solution iam getting is not even close the solution of the global analysis and first submodel analysis.

i tried to follow the description as in the documentary:

site 546

… the user may perform a submodel analysis with displacement
boundary conditions, store the forces at the boundaries in the frd-file and use
this file as global model for a subsequent submodel analysis with force boundary
conditions. In this way a correct force-driven analysis can be performed, for
instance for crack propagation analyses in the submodel (displacement-driven
analyses prevent the crack from growing).

Did you perform this test on a simple model first (as it would be advisable) ? Can you share the whole input files ?

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Yeah, like @Calc_em said, maybe a minimal example would help to debug this problem.

here are the input files:

i have the feeling that the error is lying within the .frd file. the RF values are stored for the whole mesh. i guess that if RF on the boundary nodes have to be mapped on the submodel boundary nodes, there should be only those stored in the .frd but i have not find the method to store only those values on the boundary. i hope that makes sense. thanks for the support @Calc_em and @jbr

You can use the NSET parameter for the *NODE FILE keyword to limit nodal output to a particular set of nodes.

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I just did that and the results are the same. Is there someone who does have an example file for Submodel analysis with force boundary conditions?

i reduced the model to a more simple problem with less nodes. the global frd file is called meso.frd and the RF values are only stored on the boundarys. the results in the submodel are still far away from the global model.

i manage to do it by manually mapping RF via Python from the first submodel sequence on to the next. somehow mapping RF via calculix doesnt give us the right solution. same goes for the mapping stresses via DSLOAD on the outer surface.