Learning Forum

[Dominic Richter]

Hello!

I already got some experience with Ansys Workbench but I am now facing some troubles with my current Simulation. I have never done a thermo-structural coupled analysis to mention it!

I want to simulate a linear friction welding process in 3D and the following data are available:

• Temperature dependent material parameters (thermal conductivity, heat capacity, density, youngs modulus, poission ratio, and some others....)
• Stress strain diagramm at room temperature
• And of course my geometry

So here is my question/issue: I have tried several analysis to simulate this problem (transient thermal with coupled transient structural, coupled field transient)
But it does not converge or give me any realsitic results...

To specify -> I want to simulate the whole process which includes the linear motion (I implemented it via a simple sinodal velocity), the generation of heat via the surface contact, and of course the deformation and temperature profile.

So my question would be if it is even possible to solve this problem via a thermo-mechanical coupled analysis? As I mentioned before the "Coupled Field Transient" analysis type seems reasonable to solve this problem or did I missunderstood this completly?

And is it better to implement the heat caused by the friction between the two pieces as a simple heat flow as a function of time and temperature, or over the contact itself?

Maybe someone can help me with this problem or give me some advices how to do it and if the suggestions I made are even correct?

I am thankful for everything that helps!

 

Greetings, Dominic

[Dave Looman]

In my opinion it is more practical to compute the frictional heat separately and apply it as a load instead of solving for it.  Mechanical APDL Technology Showcase Chapter 28 is an example of actually solving for the frictionally heating and it is very slow.

[Dominic Richter]

Hello Dave!

first of all thanks a lot for your support. I will take a close look into the mentioned chapter.
I also thought on splitting it up into a transient thermal part, where I introduce the frictional heat as a function of time on the rubbing surfaces, and introduce this result as a load into a transient structural analysis. The only thing that cant be computed this way is the plastic deformation during heating up since plastic deformation will occur before the final temperature is reached.
Therefore I thought of solving this friction welding problem with a coupled analysis.

Are there any other suggestions or tipps regarding this problem?

Greetings,

Dominic

[Dave Looman]

If you do a coupled analysis it will converge better if you use weak (one-way) coupling which ignores the heat produced by deformation in the bodies.  

[Dominic Richter]

Hello Dave!
Thanks again for the quick response!

How is it possible to do this? So which settings do I have to change in the analysis in the Workbench?

 

Greetings and have a nice Weekend!

Dominic

[Dave Looman]

At the bottom of the Details for the Physics Region is "Coupling Options."  For "Thermal Strain" change it to Weak.