Tanakorn,

I would review your EJ model again to make sure it is correct. Make sure you've Cnoded correctly etc. The tie-rods will asborb the pressure thrust and the thrust loads will not be transmitted to the nozzle although axial forces from your piping system will transmit to the nozzle. The joint will act rigid axially unless the piping exerts a force on the joint greater than the pressure thrust.

Kevin