i’m not sure about the possibility due to complexity. Some external mesher have this feature for splitting quadrilateral or hexahedral element in local refinement. It follows three to one transition rules like figure below. But i don’t know is Gmsh capable for such purpose.
This tool splits the whole mesh. It’s not a tool for local refining in the strict sense.
But when applying this to a submodel, it’s a “kind” of local refinement compared to the global model.
I think the last picture, where I just placed both meshes on top of each other, leads to misunderstandings.
maybe i’m overlook at thread names. My understanding in submodel is doing local analysis models by refined mesh, both have the same goal. It seems a submodel using interpolate from result file previously solved, thus make it less in resource. Current limitation or disadvantage is in defining twice of analysis setup.
Probably, due to these reasons in submodel approach cause of rarely in use compared to local mesh refinement at global model. However, it still good solution for huge/large models.
I think the main reason is to create the details only in the submodel. But I wanted to give an example when this feature can be really helpful.
There is actual no other way for mesh refinement when you have only a mesh without geometry. Before i make a feature request, i really think twice if this is a useful feature and try to give good reasons for it.
Yes but setting up a submodel in prepomax goes very fast, all you need to do is defining the result file name and select the cutting-faces for the BCs:
This is a nice idea. Currently, I would suggest the following procedure. Keep steps 1 and 2. Instead of exporting, delete the parts you do not need in the submodel. Fix the supports, loads, … Then apply step 5. For that, a feature to refine the mesh would need to be added to PrePoMax.
nice example. However, seam weld model did not explicitly define at shell global model, i guessed by simple tie constraint or tied contact type. Displacement compatibility at boundary condition of submodel may not satisfy, specific approach need to properly defined to account of lever arm fixity.
Would you think adding a gap between the parts and enlarging the submodel over the total length, to ensure the force transfer acts on the weld seam only, would be a solution?
Keep in mind that there’s both node-based (*BOUNDARY, SUBMODEL) and surface-based (*DSLOAD, SUBMODEL) submodeling. The former is normally advised for cases when more accurate displacement results are needed while the latter is advised when more accurate stress results are needed. Currently, PrePoMax supports only node-based submodeling.
indeed, seam weld model of shell element required specific approach. Similar feature implementation is available in Catia and Ansys. Ignoring weld models in global analysis will lead to results in less stiff, below simple example (discrepancy about 10% and more).
I am aware of this feature, but I have to consider what is easier to implement (Gmsh or a new procedure inside PrePoMax). Namely, inside PrePoMax geometry data is connected to the mesh and using Gmsh might break that data connection.
Maybe I’m mistaken, but my intention is that one of the shown models below could be used for a detailed “effective notch” submodel - starting with a shell model.
Why effective notch method? The evaluation seems to be the easiest for complex models - and best suited for FEM:
One problem i understand is to make sure, by connecting several parts, is that the mapped displacements to the submodel belong to the correct part of the global model. If i additionally add the seam weld to the global model, it will be even harder to separate (actual my problem with the second model).
If i don’t miss something important, at least the first model with tie constraint seems to be not too bad. With gaps between the different parts of the global model (bridged-over with tie constraints with appropriate position tolerance) and cutouts in the submodel, these mapping assignment should be clearly separated.
The idea is to have only one detailed submodel for each kind of weld seam which can be placed at different locations of a big global model.
Tips and opinions welcome.
My approach is based on a simplification (that’s normal in FEA). It’s certainly not a bad idea to take more details into account. But what exactly is missing in my model?
right, but not too simple, something like example below also simplified ones. Probably, it can have better approach since rigid zone or lever arm fixity being considered in analysis model.
Same applies to the setOrder tool:
