ASME NC-3658.3 Calculation Method for B16.5 Flanged Joints with High Strength Bolting - CAESAR II - Help

CAESAR II Users Guide (2019 Service Pack 1)

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CAESAR II
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CAESAR II Version
11.0 (2019)

Restricted to joints using flanges, bolting, and gaskets as specified in ANSI B16.5 that use bolting materials having an S value at 100°F (38°C) greater than or equal to 20,000 psi (138 MPa). CAESAR II uses the analysis method for Service Level A as stated in NC-3658.3(a)(2):

Mfs ≤ 3125(Sy/36,000)CAb

or

Mfd ≤ 6250(Sy/36,000)CAb

Where:

Mfs = Bending or torsional moment, whichever is greater, acting on the flange, and due to weight, thermal expansion, sustained anchor movements, relief valve steady state thrust, and other sustained mechanical loads. CAESAR II considers any moments developed during a non-Occasional Load Case to be Mfs.

Mfd = Bending or torsional moment, whichever is greater, acting on the flange, as defined for Mfs and but also including any dynamic loadings. CAESAR II considers any moments developed during an Occasional Load Case to be Mfd, effectively the doubling flange capacity for Occasional loadings.

Sy = Yield strength of flange material at design temperature. CAESAR II allows evaluation to be done using as many as 10 different temperatures; Sy/36,000; where Sy, is given in psi, cannot be greater than 36,000 psi

C = Bolt circle diameter

Ab = Total cross-sectional area of bolts

PD = Design pressure

CAESAR II calculates an Equivalent Stress S in the flange and compares it to Sy (or 2*Sy for occasional load cases), in the following manner:

S = 36,000* Mfs / (CAb * 3125) ≤ Min(Sy, 36000) (non-Occ)

S = 36,000 * Mfd / (CAb * 3125) ≤ 2.0 * Min(Sy, 36000) (Occ)

For systems of units that do not express stress in psi, the software converts the 36,000 values in the above equations to the appropriate set of units.

You can do flange evaluations in Static Analysis only.