Discussion Forum

Hi,

I am new to Comsol and trying to model the thermal expansion of a small plastic cube on a post. I was hoping this would be simple to model, but I am having trouble getting the expansion to act correctly. Hopefully someone can help me troubleshoot this, because I am at a loss.

I am heating and cooling a plastic cube (1cm length/width/height) from one side from -55 degC to 85 degC and I am interested in looking at the total expansion in the x and z directions. I used the "Thermal Stress" module available in Comsol 4.3b to attempt to model this.

Each time I run the program with different thermal expansion coefficients or different temperatures, it still gives me a 1mm expansion in each direction. It's as if the parameters I entered do not influence what the program is calculating for the expansion. On paper, I calculated that the total expansion when heated from room temp (~25degC) to 85degC is roughly 50um, so the 1mm that Comsol is calculating is much too high.

If you have any thoughts, I would greatly appreciate it. I have been struggling with this for days now.

Thanks!

Jessica