Hi, all,

How does CAESAR II calculate the bolting stress in the “Flange Leakage/Stress Calculations” module?
The bolting stress results from CAESAR II are much different as my calculation by hand. By comparing “flange.msg” file, I found two different points:

1. Bolting area Ab
I have 12 bolts with 28.5 mm (1.122 in), so total area is
Ab= pi /4 * 1.122² * 12 = 11.86 in²

However I got Ab= 8.74 in² in “flange.msg” file

2. Basic gasket seating width b0
Following are input values:
Facing Sketch - 6
Facing Column - 1
Nubbin Width - 0
Gasket Outer Diameter - 193.62 mm (7.623 in)
Gasket Inter Diameter - 159.78 .mm (6.291 in)
Based on ASME Sec. VIII, Div. 1, Table 2.5-2,
b0= w/8
Assumed w is calculated in Caesar from gasket outer diameter and inter diameter, so
w= (7.623-6.291)/2 = 0.67 in
then
b0= 0.67/8 = 0.083 in

However I got following results in “flange.msg” file
CONTACT WIDTH OF GASKET, N = 0.5831
BASIC GASKET SEATING WIDTH, b0 = 0.146

This looks like b0=N/4, which is however for Facing Sketch 3 and 5 in the Table 2-5.2.

Can anybody help me to explain this?

Thanks in advance