Learning Forum

[Girolamo Tagliapietra]

Hi!

My goal is to perform a combined Steady-State Thermal and Static Structural analysis of a geometry to evaluate the thermal load in combination with the built-in residual stress of the thin layers compising the solid. As in many videos, I'm trying to perform a thermal simulation to import the thermal load into the Static Structural tool and apply it to the same body, deformed because of the built-in residual stress. 

I am considering a simplified shell geometry: a 2mm x 2mm squadre with an inner and smaller one to act as an heater. I am using a shell since the thickness of the involved layers is within the 150-500 nm range. I specified the thickness of the layers after inserting the "Layered Section" and I set the analysis (attached screenshots), but I keep getting the error: 

"An error occurred inside the SOLVER module: The allowed maximum number of layers is exceeded."  

Even in case of two sole layers. The same happens in case of Transient Thermal. Is there any way to perform the thermal analysis of bodies realized by layered sections? 

If not, how to perform a combined thermal-structural analysis of thin film structures?

Thanks in advance

[Chandra Sekaran]

Layered thermal shells are not supported in Mechanical yet. There is a beta functionality but you may have issues doing the thermal - structural analysis. One issue is that general thermal-structural analyses use TEMP as the temperature dof. But with layered thermal shells (shell131 / 132) the degree of freedom is TBOT, TE1,TE2,... TTOP. This requires special handling with contact and also with coupling thermal and structural. 

[dlooman]

Even though the layers are thin you can still use solid elements.  If a well-shaped brick mesh is used the aspect ratio can be large.  In the end, layers of thin solids are about the same as a layered shell.

[Girolamo Tagliapietra]

Dear All, thank you very much for your suggestions, I'm about to make another attempt although I'm afraid that using solids instead of layered sections could be troblesome because of the elaborated geometry itself. I already tried to use solids, and if the steady thermal analysis is straightforward, the static structural analysis including the thermal load and the residual stress (imposed by INITSTATE command) led to unrealistic results (e.g. abnormal deformations)....