Learning Forum

[Mathias Giesbrecht]

Hello everyone,

I am currently working on an electrothermal simulation of a fuse and I have run into a bit of a problem. I added the "antype,trans" command to make my simulation transient, but when I ran the simulation for over three time steps, I noticed that the first step was already at 89 degrees Celsius, even though I had set the ambient temperature at 60 degrees Celsius.

I am wondering why the simulation is starting off so high in temperature and why, on the third step, the temperature is going down. Has anyone experienced a similar issue before or does anyone have any suggestions on how to troubleshoot this problem?

Any help would be greatly appreciated. Thank you in advance!

[Rahul Kumbhar]

Please check the solution output for any warnings. 

[Mathias Giesbrecht]

 

 

I get this warning: Not all components were written out, as some violate the Mechanical APDL naming convention.

And if I look into the solution information, I get these 2 warnings: 

 *** WARNING ***                         CP =       1.906   TIME= 09:57:30
 Element shape checking is currently inactive.  Issue SHPP,ON or        
 SHPP,WARN to reactivate, if desired.  

 

 

 *** WARNING ***                         CP =       4.703   TIME= 09:57:32
 Coefficient ratio exceeds 1.0e8 – Check results.  

 

 

What can I learn from these and how can I get correct solutions?

 

 

[Erik Kostson]

 

 

Hi

You can do this natively in the latest releases (say 2023 R1), so no need for any antype apdl commands.

Use the coupled field transient system (using thermal and electric conduction physics region settings - see below).

Since it is transient have a small enough time step and define the initial temp. conditions as needed (initial conditions).

All the best

Erik

 

 

[Mathias Giesbrecht]

Hi Erik,

Thanks for your help! That physics option box, I can onbly have it on the 2023 release? I am trying to download it and I'll keep you posted - thanks

Best
Mathias

 

 

 

[Erik Kostson]

yes to do a transient thermal electric analysis like you do natively and without any commands, we need to use 2023 R1 with coupled field transient system.

All the best

Erik

[Mathias Giesbrecht]

 

I have really long calculating times with the coupled field transient system but the 'old' thermo electrical system is now working correctly without a decrease of temperature toward the end.
Best
Mathias