Single and Double Flanged Bends or Stiffened Bends - CAESAR II - Reference Data

CAESAR II Applications Guide

Reference Data

Single- and double-flanged bend specifications affect only the stress intensification and flexibility of the bend. There is no automatic rigid element (or change in weight) generated for the end of the bend. Single- and double-flanged bends are indicated by typing a 1 or 2 to define the Type in the bend auxiliary input. Rigid elements defined before or after the bend do not alter the stiffness of the bend or its stress intensification factors.

When specifying single-flanged bends, it does not matter on which end of the bend you place the flange.

If you want to include the weight of the rigid flange at the bend ends, then put rigid elements (whose total length is the length of a flange pair) at the bend ends where the flange pairs exist.

As a guideline, British Standard 806 recommends stiffening the bends whenever a component that significantly stiffens the pipe cross section is found within two diameters of either bend end.

The flanges in the figures below are modeled only to the extent that they affect the stiffness and the stress intensification for the bends.