Material thermal expansion coefficient can be defined for FEM but not the reference temperature

[FEA-eng]

Is there an existing issue for this?

• I have searched the existing issues

Problem description

Thermal material properties include the expansion coefficient but it should be also possible to specify the reference temperature (the temperature at which there are no thermal strains). CalculiX handles it this way:

*EXPANSION, ZERO=reference_temperature
expansion_coefficient

If not specified, it's assumed to be 0 which is often not the desired behavior.

It could be added as a separate material property to make it simple.

@davesrocketshop Can you add it at some point?

P.S. It would be nice to have Material selectable under Subproject(s) affected.

Full version info

OS: Windows 10 build 19045
Word size of FreeCAD: 64-bit
Version: 0.22.0dev.36391 (Git)
Build type: Release
Branch: main
Python 3.10.13, Qt 5.15.8, Coin 4.0.2, Vtk 9.2.6, OCC 7.6.3
Locale: Polish/Poland (pl_PL)

Subproject(s) affected?

Other (specify in description)

Anything else?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[davesrocketshop]

Is a separate material property appropriate? It could also be added as a property to Thermal.yml if that's more appropriate

[FEA-eng]

Is a separate material property appropriate? It could also be added as a property to Thermal.yml if that's more appropriate

I think that it should be a new property in the Thermal group:

It could be also named Thermal expansion reference temperature for more clarity bit it would be a rather long name so maybe with some abbreviations? Like Thermal expansion ref. temp. ?