Specifies the thickness of the bend if that thickness is different than the thickness of the matching pipe. If the thickness is greater than the matching pipe wall thickness, then the inside diameter of the bend is smaller than the inside diameter of the matching pipe.
Typical units (depending on your unit system):
-
in
-
mm
-
cm
CAESAR II calculates section modulus for stress computations based on the properties of the matching pipe as defined by the codes.
The pipe thickness is used twice when calculating SIFs and flexibility factors; once as Tn, and once when determining the mean cross-sectional radius of the pipe in the equation for the flexibility characteristic (h):
h = (Tn)(R) / (r2)
Tn = Thickness of bend or fitting
R = Bend radius
r = Mean cross-sectional radius of matching pipe
= (OD - WT) / 2
OD = Outside Diameter of matching pipe
WT = Wall Thickness of matching pipe
Most codes use the actual thickness of the fitting (this entry) for Tn, and the wall thickness of the matching pipe for the calculation of the mean cross-sectional radius of the pipe (the WT value). More specifically, the individual codes use the two wall thicknesses as follows:
Code |
For Tn |
For Mean Radius Calculation |
---|---|---|
B31.1 |
Fitting |
Fitting |
B31.3 |
Fitting |
Matching Pipe |
B31.4 |
Fitting |
Matching Pipe |
B31.5 |
Fitting |
Matching Pipe |
B31.8 |
Fitting |
Matching Pipe |
B31.8 Ch VIII |
Fitting |
Matching Pipe |
SECT III NC |
Fitting |
Matching Pipe |
SECT III ND |
Fitting |
Matching Pipe |
Z662 |
Matching Pipe |
Matching Pipe |
NAVY 505 |
Fitting |
Fitting |
B31.1 (1967) |
Fitting |
Fitting |
SWEDISH |
Fitting |
Matching Pipe |
BS 806 |
N/A |
N/A |
STOOMWEZEN |
N/A |
N/A |
RCC-M C/D |
Matching |
Matching Pipe |
CODETI |
Fitting |
Fitting |
NORWEGIAN |
Fitting |
Fitting |
FDBR |
Fitting |
Fitting |
BS 7159 |
Fitting |
Fitting |
UKOOA |
Fitting |
Fitting |
IGE/TD/12 |
Fitting |
Fitting |
EN-13480 |
Fitting |
Matching Pipe |
GPTC/Z380 |
Fitting |
Matching Pipe |
The bend fitting thickness (FTG) is always used as the pipe thickness in the stiffness matrix calculations. However, the thickness of the matching pipe (WT) is always used in the bend stress calculations.