FEM/Frame Analysis alternative design workflow

[SMAH]

I am from the structural analysis and design side, and I am not very familiar with FreeCAD. I want to use it using a different workflow to that shown on most of the tutorials..

Rather than create the final solid model in FreeCAD and then mesh it into tetrahedral elements in order to carry out the analysis (which is common in mechanical workflows), I wish to create a structural model in FreeCAD with linear elements (to represent beam sections) and shell planes and surfaces (to represent walls, slabs, shells, and plates) with materials and section properties entered into FreeCAD, and mesh the structural model with GMSH/Netgen. The modelling capabilities here should be that of a general purpose structural programme. Ideally the structural analysis mesh would be viewable for checking and entry of structural properties in FreeCAD. The structural analysis would then be run (using Calculix or another programs via GMSH export), and the member sizes and element thicknesses finalized. Only following this, the structural model would then be converted into a full 3D model by expanding the 1D beam elements and shell elements to 3D to produce a solid CAD model from which drawings, sections, and details can be produced.

This is the normal workflow for civil engineering structures as it is normally necessary to model the structure for analysis using 1D beam elements and shell elements in order to reduce the number of degrees of freedom in the model to a manageable size due to the complexity of the structure compared to mechanical components. Also a number of iterations and changes is usually required to make the structure work, and to optimise it for cost. It would also waste a lot of time and abortive work if each of these iterations and changes had to be made in the full solid model before the analysis can be run. This approach is therefore a way of rapidly generating a structural analysis model, viewing it, changing it, and then converting it into a solid model (with BEM data incorporated) in order to produce drawings and details and BEM model for interaction with others - essentially like the arch module but more flexible and with a structural design module preceding it, and the workflow streamlined by avoiding re-entry of data that has already been entered.

Can you tell me whether this workflow is possible in FreeCAD at the moment, and if not, where I can get documentation on the programming interfaces with GMSH and Calculix to allow creation of a structural model export and import interfaces and an idealised structural modeller module/interface for FreeCAD.

[johnwang]

You could try frame3dd, nastran95/mystran solver.

[bernd]

You could do this in FreeCAD already. Just modell faces and edges in FreeCAD and make a analysis out of it. See the FreeCAD FEM examples gui in utilities for examples in this regard.

But how about this? Modell you solid Arch modell in FreeCAD. The structural lines will be created automatically. Use the structural lines to make a FEM from it or export it to IFC and use it in another analysis software. See https://forum.freecadweb.org/viewtopic. ... 20#p507149