I have done a static analysis of the quick opening of a pressure vessel using two different material approach.
in the first one all the material properties are set at the design temperature (250 °C): i.e. Youngs modulus and expansion coefficient are set at the appropriate values;
in the second one I have used functions vs. temperature to define Youngs modulus and expansion coefficient, and I have add a body load activated at the default temperature (250 °C).
I think the results have to be quite similar, but with great surprise they are different!
In the first analysis Femap stop (without errors) in a few time after 1 or 2 iteration and don't seems to keep togeter the parts glued (the teeth of the mating flanges are meshed with different approach hex and tetra);
In the second Femac required a lot of iteration and hours for the result, but I don't unterstand why, if it is my error or Femap limit.