Simulation error using two Constraint Heatflux

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Eduardo1
Posts: 23
Joined: Wed Aug 25, 2021 1:56 am

Simulation error using two Constraint Heatflux

Post by Eduardo1 »

Good afternoon, I did a simple simulation using two constraint heatflux, I used a cube, the material was Calculix-Steel, the both constraint heatflux are in the top and the bottom of the cube, I selected the higgest mesh, the top constraint heatflux is -0.50 W/m^2 and the bottom is 1.00 W/m^2, the constraint initial temperature was 300 K, I am using Freecad 0.20, everything is fine in "write .inp file" but there is an error when I "run Calculix", What I am doing wrong?

Beforehand thank you so much.

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.26858 (Git)
Build type: Release
Branch: master
Hash: e209bc706d35121098f9bac779bc6b09c24ddd95
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.3
Locale: Spanish/Mexico (es_MX)
Attachments
error.png
error.png (134.22 KiB) Viewed 1401 times
bottom.png
bottom.png (130.82 KiB) Viewed 1401 times
top.png
top.png (132.22 KiB) Viewed 1401 times
meshing.png
meshing.png (131.96 KiB) Viewed 1401 times
material.png
material.png (129.49 KiB) Viewed 1401 times
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NewJoker
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Joined: Sun Oct 11, 2020 7:49 pm

Re: Simulation error using two Constraint Heatflux

Post by NewJoker »

Can you attach the .FCStd file ? Are there any additional error messages in the Report View window ? So far I can only suspect that the problem is caused by the lack of mechanical constraints (that's a thermomechanical, not pure thermal analysis after all).

By the way, the mesh is definitely too coarse.
Eduardo1
Posts: 23
Joined: Wed Aug 25, 2021 1:56 am

Re: Simulation error using two Constraint Heatflux

Post by Eduardo1 »

NewJoker wrote: Tue Jan 18, 2022 9:59 pm Can you attach the .FCStd file ? Are there any additional error messages in the Report View window ? So far I can only suspect that the problem is caused by the lack of mechanical constraints (that's a thermomechanical, not pure thermal analysis after all).

By the way, the mesh is definitely too coarse.
Sure, I am going to attach it, sorry for that.
Attachments
exampleproject.FCStd
(29.43 KiB) Downloaded 22 times
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NewJoker
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Re: Simulation error using two Constraint Heatflux

Post by NewJoker »

The analysis doesn't converge with these boundary conditions - the solver can't find the steady-state solution. It should work if you switch to transient but make sure that thermal constraints are correct in this case. They should correspond to a real-life conditions of a structure that you want to analyze or (when it's just a theoretical consideration) at least make sense in terms of underlying physics.
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