# Temperature cycling

I’m trying to set up a simulation to study the effects of temperature cycling on some parts. I have a transient thermomechanical simulation, and i set up a fixed temperature boundary condition (I assume this should only be applied to external faces?). I entered times and temperatures of the cycle, but I have a couple questions:
1.) Do I assume linear interpolation when the temperature changes, or is it going to be step changes? I don’t see anywhere to specify that.
2.) If I want to do a bunch of cycles, say 1000, is there a way to do that without entering the information for all 1000 cycles in a table?

Thanks in advance!

Hey there!

Please always include the URL to your project so we can provide the best possible support.

To answer your questions:

Yes, linear interpolation between the specified points.

You can use a formula instead of a table, e.g., a sine function.

In any case, why do you need to simulate 1000 cycles? What nonlinear effect do you need to consider for that many cycles? What analysis method are you following for this?

1 Like

Thanks for the response, sorry the link is below. I clearly need additional boundary conditions. I don’t need 1000 cycles it was just an example…just trying to get my feet wet with using the software beyond the tutorials and this seemed like a simple test.

https://www.simscale.com/workbench/?pid=7813288797666347571&mi=spec%3A73409745-34ed-4cda-ab36-3e451fde0ac7%2Cservice%3ASIMULATION%2Cstrategy%3A9&ps=analysis%2FThermalMechanical--oneOf%2FinitialConditions%2Ftemperature

Ok, let us know if you have more questions!

So I can do a transient study with a temperature cycle or just do a steady-state study at the max and min, right? Is there any way to analyze thermal fatigue that develops over many cycles? Thanks so much for your help.

You can perform transient, non-linear or steady state simulations depending on what you need. If for example you are considering plasticity, then the non-linear is a must. Same about dynamic effects.

The fatigue assessment is performed outside of SimScale, just download the results, perhaps with Result control items, and proceed with the methodology you chose.

OK thanks again…for my example there are 2 parts in contact with each other. I noticed if I try to apply the thermal boundary condition to the volumes it doesn’t like it, since the internal surfaces in contact with each other already have a defined relationship. So in that case can I only apply the b.c. to the external surfaces or is there some other way? Thanks!

This way should be ok.

hello, and you could throw off your link again, it is not displayed.
thank you very much, arthur

BlockquoteThanks for the response, sorry the link is below. I clearly need additional boundary conditions. I don’t need 1000 cycles it was just an example…just trying to get my feet wet with using beyond the tutorials and this seemed like a simple test the [time tracking software (Employee time tracking software - WorkTime)
https://www.simscale.com/workbench/?pid=7813288797666347571&mi=spec%3A73409745-34ed-4cda-ab36-3e451fde0ac7%2Cservice%3ASIMULATION%2Cstrategy%3A9&ps=analysis%2FThermalMechanical–oneOf%2FinitialConditions%2Ftemperature

in fact, very few people need 1000 cycles … I absolutely agree with you