You must be aware that in most of the situation flanges are attached near elbows or bends (Near Control Valve assembly and equipment nozzles). This rigid attachment exerts a severe restraining force to the flexibility of the bend, thus reducing the flexibility of the bend and increasing the force and moment in the nearby support or nozzle. ASME B 31.3 Code provides two correction factors C1 and C2 to take care of the same effect.
Flanged Bend Modeling in Caesar II
In caesar, the same can be easily taken care of by modeling flanged elbow as mentioned below.
Sometimes dummy attachments at elbow also provide a similar effect that is why a few organizations have the practice of using flanged elbow while modeling the trunnions from the elbow.
Single or Double Flange Option should be applied to Stress Analysis if there is any flanges or valves (heavy/rigid body) within two diameters of the ending weld point of the bend.