Formulas: plain material and welded joints

Equation A-3-1

(a) For stress categories A, B, B′, C, D, E, and E′, the allowable stress range, FSR, shall be determined by Equation A-3-1 or A-3-1M, as follows:

F_{S R}=1,000\left(\frac{C_{f}}{n_{S R}}\right)^{0.333} \geq F_{T H}

F_{S R}=6900\left(\frac{C_{f}}{n_{S R}}\right)^{0.333} \geq F_{T H}

where

$C_{f}$ = constant from Table A-3.1 for the fatigue category

$F_{S R}=$ allowable stress range, ksi (MPa)

$F_{T H}=$ threshold allowable stress range, maximum stress range for indefinite design life from Table A-3.1, ksi (MPa)

$n_{S R}=$ number of stress range fluctuations in design life

(b) For stress category F, the allowable stress range, $F_{S R}$ , shall be determined by Equation A-3-2 or A-3-2M as follows:

F_{S R}=100\left(\frac{1.5}{n_{S R}}\right)^{0.167} \geq 8 \mathrm{ksi}

F_{S R}=690\left(\frac{1.5}{n_{S R}}\right)^{0.167} \geq 55 \mathrm{MPa}

F_{S R}=1,000 R_{P J P}\left(\frac{4.4}{n_{S R}}\right)^{0.333}

F_{S R}=6900 R_{P J P}\left(\frac{4.4}{n_{S R}}\right)^{0.333}

$R_{P J P}$ , the reduction factor for reinforced or nonreinforced transverse PJP groove welds, is determined as follows:

R_{P J P}=\frac{0.65-0.59\left(\frac{2 a}{t_{p}}\right)+0.72\left(\frac{w}{t_{p}}\right)}{t_{p}^{0.167}} \leq 1.0

R_{P J P}=\frac{1.12-1.01\left(\frac{2 a}{t_{p}}\right)+1.24\left(\frac{w}{t_{p}}\right)}{t_{p}^{0.167}} \leq 1.0

F_{S R}=6900 R_{F I L}\left(\frac{4.4}{n_{S R}}\right)^{0.333}