Access to nodal results on element by element basis

[HarryvL]

Hi, I want to do some post processing for which I need to cycle through the elements of the result mesh and for each element access the element nodal results and nodal coordinates. So not simply run through all nodes, but access them on an element by element basis. How can I best do that? Thanks. Harry

[bernd]

load FEM 3D example

Code: Select all

mesh = App.ActiveDocument.Box_Mesh.FemMesh

for v in mesh.Volumes:
    nodes = mesh.getElementNodes(v)
    print('volume: {0} --> nodes: {1}'.format(v, nodes))

[bernd]

including the displacement result for each element node ...

Code: Select all

mesh = App.ActiveDocument.Box_Mesh.FemMesh
results = App.ActiveDocument.CalculiX_static_results

for v in mesh.Volumes:
    nodes = mesh.getElementNodes(v)
    print('volume: {0} --> nodes: {1}'.format(v, nodes))
    for n in nodes:
        print('  node: {0} has displacement: {1}'.format(n, results.DisplacementLengths[results.NodeNumbers.index(n)]))

[bernd]

ahh mesh should be the result mesh not the input mesh!

[HarryvL]

Fantastic Bernd, thanks.

I have an idea of how to visualize stress trajectories in a solid. For this I need to integrate principal stress intensity and direction over the full mesh. That's where I needs this.

[bernd]

I have an idea of how to visualize stress trajectories in a solid. For this I need to integrate principal stress intensity and direction over the full mesh. That's where I needs this.

similar to this ? https://forum.freecadweb.org/viewtopic.php?t=24637

[HarryvL]

What I have in mind is different in that it plots continuous lines, showing the flow of load from application to support ... more like this:

Trajectories_1.jpg (9.05 KiB) Viewed 1639 times

Trajectories_2.gif (32.36 KiB) Viewed 1639 times

[bernd]

cool ...

[Jee-Bee]

Would this be a kind of vector views?

[HarryvL]

No it would be contour lines. The tangent to the line gives the direction of the principal stress and closeness of the lines gives the stress intensity. It's basically a "stress flow" plot.