¿What about a generic Field Output called NodeOutputGradient or simply Gradient based on Node Outputs?
Additionally, Vector Fields could show the arrow map when clicking on the header.
It would be nice to have this feature for oriented stresses as well. I really miss vector output for stress analysis.
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Workaround for the first time:
- Calculation in PrePoMax
- Converting frd to rmed (Calmed8 utility)
- Open rmed in Gmsh
- Use the “Gradient” plugin
Best export result, example PNG
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FreeCAD FEM now supports glyph (symbol) plots of vector variables. It can open CalculiX’s .frd files but it’s based on ParaView so one may convert the .frd file to vtk and use the Glyph filter there.
I like this workflow better. As I mentioned, the gradient could be a filter that is used in post-processing.
I will look into it to see how much work this will be.
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One thing I’d like to highlight here is that we are using a steady-state heat transfer step which only allows us to solve electrostatics problems by equivalence of the governing equations (basically solving Poisson’s equation). This means that we are studying electric field resulting from stationary charges. Assuming constant electric conductivity, we can determine the electric field in a conductor and then use this as a heat source for Joule heating calculation. But in more complex cases, a different analysis type usually called static or steady current (DC) conduction is needed. This is mentioned in the references for the circular plate example (“DC Conduction Steady State” solution type in Simcenter/NX). There one can apply electrical potential BCs but also current/current density loads. So we can use current sources and study current flow paths. Unfortunately, this type of analysis is not supported by CalculiX (but Elmer has it, now also available in FreeCAD FEM).
MAGNETICS, integrated in NX / Simcenter or as standalone, well known as NX-Magnetics, is a comprehensive FEM software package to simulate and optimize electromagnetic devices. It is used by industry and science and either integrated in the Siemens NX / Simcenter™ software system or available as a standalone product. Development, support and distribution is achieved by Dr. Binde Ingenieure GmbH, solution partner of Siemens Industry Software GmbH. The calculation module NX-Magnetics is a commercial version of GetDP. GetDP is an open source software that is also used by industry and science around the world. DC Conduction Steady State solution type of analysis is supported by Gmsh&GetDP.
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I’m new to this area of FEA but it has my attention.
If we are using a STEADY state HEAT transfer equation, aren’t we solving STEADY State CURRENT configurations by analogy?
That covers more problems. Stationary charge would only be one of them in which Current is Steady with value=0.
I’m finding the Resistance at the circular plate by imposing Potential =0 on one side and 1 A at the other. Potential drop is directly the plate resistance.
Vf-Vo/I=R
Vf-0/1=R
Vf=R
Is that wrong?
I’m also not an expert in terms of EM simulations but the equations in electrostatics are indeed similar to the ones in steady currents. The tables here show it nicely:
But they are based on different laws and use different quantities.
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A little more theory (the “internal kitchen” of GetDP), for those who might be interested…
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