For studies with a large number of bodies, the new submodelling feature allows you to improve the results at critical areas without having to rerun the analysis for the whole model. Refining the mesh for a selected portion of the model and rerunning the analysis only for the submodel saves computation time.
After you run your problem with a relatively coarse mesh, you may define a group of bodies in a submodel where stresses may not have been calculated accurately due to sharp corners, or geometric and load non-uniformities.
The mesh of the bodies inside the submodel is refined, and you can rerun the problem to improve results for the submodel only, without recalculating results for the rest of the model.
A submodelling study is derived from an eligible parent study. The parent study should meet these conditions to be eligible for a submodelling study:
• The study type must be Static or Nonlinear static with more than one body and not be a submodelling study itself. The parent study cannot be a 2D Simplification Study.
• The selected bodies that compose the submodel may not have No penetration contact with unselected bodies that result in contact pressure across the cut boundary.
• The selected bodies that compose the submodel may not share connectors with unselected bodies.
Submodelling is based on the St. Venant’s principle which states that the stresses reasonably distant from an applied load on a boundary are not significantly altered if this load is changed to a statically equivalent load. The distribution of stress and strain is altered only near the regions of load application.
You may cut a portion of the model and run analysis only for the selected portion provided that displacements are properly prescribed at the boundaries of the cut. If displacements at the boundaries of the cut are calculated accurately at the first run, then these displacements may be considered as boundary conditions for the submodel run.
The cut boundary of the submodel cannot cut through a bonded contact defined by either beam-to-beam joints or shell edge-to-shell edge joints. The boundaries of the submodel must also be adequately far from stress concentration areas.
Feel free to also have a look at the video below, for a quick summary on these new features and improvements.