Dear Simulia-Community,

I am currently working on a rather simple heat transfer model. I have two metal parts which in the lower picture are the base plate/table and the stamp coming from the top. There are also two (or rather three) CFRP parts, each of which is modelled as 12 partitions of the same solid, with different oriented orthotropic properties. (Not the perfect way, but this is the way the UMAT will work, which I will implement after)

There is a heat source applied right between the two CFRP parts on the right. What I want is to simulate how the heat is transferred into the parts and adjacent parts.

However I came across a rather unusual occurence, which you can see in both pictures below. There are some sort of "stripes" appearing on one of the parts, with indivual nodes gaining a temperature of +4000°C and -2000°C, which absolutely is out of range for my results. I have only limited experience in Abaqus and have not seen this type of error before. The part where these strips appear is the exact same as the other ones, where these appear not as prominently. Apart from that I checked that everything else is exactly the same as well.

This of course causes some problems with convergence and makes my results unreliable.

Has anyone of you any idea why this might occur or is this maybe a common occurence, due to a common mistake? :)

Any help would be fantastic!

I am using C3D8T elements, thermal conductivity for the material is orthotropic with 5 in "fibre" direction and 0.5 perpendicular to "fibre" direction.