Dear fmk and all,
I would like to implement Scaled Boundary Finite Element method (SBFEM)[Wolf, 2003; Wolf and Song, 2000; Song and Wolf, 1996] in OpenSees.
As is well known, SBFEM combines the advantages of FEM and Boundary Element Method (BEM), while disadvantages of both are avoided. This method is particularly suited for DSSI analysis. In coupled FEM-SBFEM approach, The non-linearity in the near field may be handled by FEM while radiation condition in the far-field may be handled using SBFEM. This is the motivation of my proposal.
I sincerely believe, OpenSees is one of the best platforms for this purpose. This will enhance the capability of OpenSees for more realistic DSSI analysis, compared to the presently available approximate spring-dashpot models. Also the method may be extended for fracture-mechanics applications later.
My tentative plan is to
1. have some kind of new model builder (say "model SbfeBuilder" command or something of that sort) which would be a part of overall model.
2. It will generate its own SBFE model by accessing the normal model builder objects (viz. nodes/elements/materials) and generate the [K], [C] and [M] matrix for the SBFE part of the model
3. The near-field part of the overall model will be generated as usual in OpenSees
4. Both will be coupled using equalDOF constraint of the dofs at the interface of the two model regions (near-field and far-field).
5. The SBFE matrices will be finally assembled with the corresponding FE matrices and solved by usual OpenSees solvers.
I would like to know your comments on the feasibility of such implementation in OpenSees. I invite any other suggestions on the matter.
Looking forward to your expert comments.