e.g. Sealed air in a container at room temperature. Heat-up to 300°C. What's the stress on container?
This is the way i would do it:
1: CAD container
2: Measure internal volume
3: Use the general gas law to calculate the pressure after heating.
4: Plug in the resulting pressure in a normal stress analysis (static study) where you apply an internal pressure to your container. Don't forget to add an external pressure of 100 kPa as well, unless your container is surrounded by vacuum.
The general gas law is P1*V1/T1 = P2*V2/T2, that can be rearranged and simplified to P1*T2 / T1 = P2 (assuming your container is not affected by thermal expansion, I.E. assuming the volume is constant). Note that calculations has do be done in absolute units, not relative (i.e. use absolute pressure, use Kelvin not Fahrenheit).
if you use 100 kPa and 25°C (common standard pressure and temperature) as initial conditions, and the container volume is 1000 cm3, the resulting pressure would be 192.235 kPa when the air is 300°C. Again this does not take expansion of the container into account (neither expansion from temperature nor pressure/stress).