I have created the model of a closed container (cuboid) and inside this container is a liquid that expands due to thermal loading (temperatures). The expansion then induces stress in the container walls.
For the Container I have created a 2D Shell Mesh and for the liquid a detached 3D Hexa Mesh of the same size (fully filled container). Then I created contacts between the nodes of the liquid mesh and the elements of each surface so that it is kept inside the container and creates pressure.
My question is now how do I define the matrerial properties of the liquid inside the container correctly and did I define the contacts correctly?
I could not find any options to define a liquid with the thermal expansion coefficient. So far I have defined it as a MAT1 PSOLID Material (with the bulk modulus as e modulus):
[System: mm-t-s]

This how I created the contacts (overall 6 contact definitions, one for each surface):

But solving it like that leads to high stresses (in picture T = 300K, so only increased by 6,85K compared to TREF) and also the displacement shows that the Liquid (blue in picture) expands more than the surfaces (so its not inside anymore).

I would appreciate if anyone could help with these problems or has ideas how to solve them.