FSI Staggered Simulation

[Spyros07]

Hello everyone!!!

I would like to perform a staggered FSI simulation in NASTRAN. Initially, the aerodynamic loads, obtained via an in-house code, are applied to the FE model in NASTRAN. The linear solver SOL 101 is then used to calculate the displacements. The deformed structure is then used to recalculate the aerodynamic loads and obtain new displacements. This aeroelastic cycle will be repeated until displacements and loads converge. My question is if there is a way in NASTRAN to include the prestress state incurred by the previous aeroelastic cycle. Can it be done via a restart analysis or is a more sophisticated solver needed? Thanks in advance!

 

[dmapguru]

Restarts are not the way to go - there is too much baggage to drag around like internal stress states. SOL 101 isn't a good bet either as it has no facility for pre-stress.
If you are using MSC Nastran, take a look at SOL 400 with openFSI. This is an interface developed originally to connect to a CFD code in a co-simulation nonlinear transient solution, but it also provides access to static capabilities along the lines you require. There is a table lookup capability described in one of the earlier release guides where the loads are obtained from a set of previously computed wind-tunnel data, but it is not that much more difficult to make this into a procedure that computes the loads from responses output from the current deformed state. MSC has developed a capability you describe in an "addon" called the HSA toolkit (Hybrid Static Aeroelasticity) which provides loads mapping and other clever stuff.

DG

 

[Spyros07]

Thank you very much for your prompt response dmapguru!

Unfortunately i do not have access to the openFSI and HSA toolkits. Do you think that writing the element stresses from the previous iteration via the ISTRESS entry for the next iteration within the environment of the SOL400 is the way to go? Thank you once again.