Thermal Simulation- Stiffness matrix singular or non-positive definite

[Anonymous]

Hello everybody!

For my thesis I´m trying to make a thermal simulation of a heating element I´m using. My skills in Fusion 360 are those of a beginner, since I´m new to this programm. I designed the heating element, clicked on thermal study, chose the materials, generated the mesh, chose the loads as follows:  applied temperature on the lower part of the element (220°C) and convection on the 40 plates. After clicking pre-check and solve this message arrives and my simulation fails: Stiffness matrix singular or non-positive definite. Where am I wrong?

Thx in advance,

Matei 🙂

[Anonymous]

Do you have contacts defined?

I cant open your file right now but I will take a look at it later today if your question hasn't already been answered.

Also, an applied temperature probably isnt the correct load because your element will be power limited. That is unless the element itself is being heated by something else with a very high power output relative to your elements ability to dissipate heat.

[Anonymous · Accepted solution]

The part linked in this thread didn't have the simulation results so I couldn't see the actual failure. I also tried to duplicate the failure and couldn't. 

So I just put together a REALLY quick video to detail how I would solve this problem given the loads you have defined. This is a very summarized process so please feel free to ask questions. 

[Anonymous]

Sorry for the late response. Veeeeeery nice of you to take the time and create the video. Much appreciated!

Regards,

Matei