Hi ,

I m fresher to stress analysis.

I know manual calculation for sustained stress.

Pls help me with Expansion Stress calculation as per 31.3 code.
what is the equation for calculating axial force due to expansion.

That's the whole idea of CAESAR II.

Model system stiffness (K) and then calculate the thermal load on each piping component (assuming each component is anchored) (F) and then solve for X in F=KX. This X is the position of each node in space when the system is in equilibrium with those thermal loads. With these positions known, the internal forces and moments of each component can be derived. And one of these internal forces is your axial force due to expansion.