Thank you for your response.
I am doing a static structural simulation with a thermal condition where I increase the temperature of the barrel from 25 to 90┬░C. My goals are to see the deformation in the lenses inside and evaluate the distance the lenses are displaced. I guess this could be called as a thermal-structural simulation.
The idea was to exclude the base plate from the simulation. I only simulate the barrel with the lenses and spacers inside.
What would you suggest if I don't want to include the plate?

Best regards Amit