# Uncoupled thermal transient analysis

**URL:** <https://calculix.discourse.group/t/uncoupled-thermal-transient-analysis/2892>\
**Category:** Advanced features\
**Created:** [October 21, 2025, 6:21am UTC](https://calculix.discourse.group/t/uncoupled-thermal-transient-analysis/2892 "2025-10-21T06:21:47Z")\
**Posts on this page:** 1\
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**Author:** ![tommow](https://avatars.discourse-cdn.com/v4/letter/t/8491ac/32.png) [@tommow](https://calculix.discourse.group/u/tommow)\
**Post date:** [October 21, 2025, 6:21am UTC](https://calculix.discourse.group/t/uncoupled-thermal-transient-analysis/2892/1 "2025-10-21T06:21:47Z")

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Hello,  
i tried a uncoupled temperaturs-displacement analysis of an upsetting process..  
When I set the temperature as a fixed value, the purely mechanical analysis converges successfully. However, in the sequential thermo-mechanical coupling analysis, it fails to converge. Then, I set the coefficient of thermal expansion to zero — theoretically, this should eliminate any thermal effect on the mechanical response — but the mechanical analysis still fails to converge, with the residuals diverging rapidly.  
Any ideas?

Br,  
Miles

inp.file

> **[Dropbox](https://www.dropbox.com/scl/fi/tbffu15f4hd0t6rgv84pa/upsetting.inp?rlkey=me04w2ia891dyoyg86bmt3ymz&st=i3ocaof9&dl=0)**

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