Write and test computer subroutines or procedures that will implement
(a) Table 6–2, returning a, b, C, and \bar{k}_{a} .
(b) Equation (6–20) using Table 6–4, returning k_{b} .
(c) Table 6–11, returning α, β, C, and \bar{k}_{c} .
(d) Equations (6–27) and (6–75), returning \bar{k}_{d} \text { and } C_{k d} .
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Eq. (6-19): k_{a}=a S_{u t}^{b}
Eq. (6-20): k_{b}= \begin{cases}(d / 0.3)^{-0.107}=0.879 d^{-0.107} & 0.11 \leq d \leq 2 \text { in } \\ 0.91 d^{-0.157} & 2<d \leq 10 \text { in } \\ (d / 7.62)^{-0.107}=1.24 d^{-0.107} & 2.79 \leq d \leq 51 mm \\ 1.51 d^{-0.157} & 51<d \leq 254 mm \end{cases}
Eq. (6-27): \begin{aligned}k_{d}=& 0.975+0.432\left(10^{-3}\right) T_{F}-0.115\left(10^{-5}\right) T_{F}^{2} \\&+0.104\left(10^{-8}\right) T_{F}^{3}-0.595\left(10^{-12}\right) T_{F}^{4}\end{aligned}
where 70 \leq T_{F} \leq 1000^{\circ} F.
Eq. (6-75): k _{d}=\bar{k}_{d} L N (1,0.11)
where \bar{k}_{d}=k_{d} given by Eq. (6–27),
Table 6–2 Parameters for Marin Surface Modification Factor, Eq. (6–19) |
Surface Finish | Factor a | Exponent b |
|
S _{\text {ut}}, \text { kpsi } | S_{u t}, M P a | |||
Ground | 1.34 | 1.58 | −0.085 | |
Machined or cold-drawn | 2.70 | 4.51 | −0.265 | |
Hot-rolled | 14.4 | 57.7 | −0.718 | |
As-forged | 39.9 | 272. | −0.995 |
Table 6–4 Effect of Operating Temperature on the Tensile Strength of Steel.* (S_{T} = tensile strength at operating temperature; S_{R T} = tensile strength at room temperature;0.099 \leq \hat{\sigma} \leq 0.110) |
Temperature, °C | S_{T} / S_{R T} | Temperature, °F | S_{T} / S_{R T} |
20 | 1.000 | 70 | 1.000 | |
50 | 1.010 | 100 | 1.008 | |
100 | 1.020 | 200 | 1.020 | |
150 | 1.025 | 300 | 1.024 | |
200 | 1.020 | 400 | 1.018 | |
250 | 1.000 | 500 | 0.995 | |
300 | 0.975 | 600 | 0.963 | |
350 | 0.943 | 700 | 0.927 | |
400 | 0.900 | 800 | 0.872 | |
450 | 0.843 | 900 | 0.797 | |
500 | 0.768 | 1000 | 0.698 | |
550 | 0.672 | 1100 | 0.567 | |
600 | 0.549 | |||
*Data source: Fig. 2–9. |
Table 6–11 Parameters in Marin Loading Factor |
k _{ c }=\alpha \overline{ S }_{ u }^{-\beta} L N ( 1 , C ) | |||||
Mode of Loading | \alpha | |||||
kpsi | MPa | \beta | C | Average k_{c} | ||
Bending | 1 | 1 | 0 | 0 | 1 | |
Axial | 1.23 | 1.43 | −0.0778 | 0.125 | 0.85 | |
Torsion | 0.328 | 0.258 | 0.125 | 0.125 | 0.59 |