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Torispherical ends for external pressure

Values for calculation

$ T $ $ \mathrm{°C} $
$ T_{test} $ $ \mathrm{°C} $
$ P $ $ \mathrm{MPa} $
$ P_{test} $ $ \mathrm{MPa} $
$ R $ $ \mathrm{mm} $
$ e_a $ $ \mathrm{mm} $
$ R_{p0.2/T} $ $ \mathrm{MPa} $
$ R_{p0.2/T_{test}} $ $ \mathrm{MPa} $
$ R_{p1.0/T} $ $ \mathrm{MPa} $
$ R_{p1.0/T_{test}} $ $ \mathrm{MPa} $
$ E_T $ $ \mathrm{MPa} $
$ E_{T_{test}} $ $ \mathrm{MPa} $

Calculation

Nominal elastic limit for shell for normal operating load cases

$\text{if }\ \text{type }$$\text{of }$$\text{material}= \text{Austenitic steels}$
$$σ_e=\cfrac{R_{p0.2/T}}{1.25}$$
$\text{else}$
$$σ_e=R_{p0.2/T}$$

Nominal elastic limit for shell for testing load cases

$\text{if }\ \text{type }$$\text{of }$$\text{material}= \text{Austenitic steels}$
$$σ_{e_{test}}=\cfrac{R_{p0.2/T_{test}}}{1.25}$$
$\text{else}$
$$σ_{e_{test}}=R_{p0.2/T_{test}}$$

Pressure at which mean circumferential stress in cylindrical or conical shell midway between stiffeners, or in a spherical shell, reaches yield point for normal operating load cases

$$P_y=\cfrac{2\cdot σ_e\cdot e_a}{R}$$

Pressure at which mean circumferential stress in cylindrical or conical shell midway between stiffeners, or in a spherical shell, reaches yield point for testing load cases

$$P_{y_{test}}=\cfrac{2\cdot σ_{e_{test}}\cdot e_a}{R}$$

Theoretical elastic instability pressure for collapse of a perfect cylindrical, conical or spherical shell for normal operating load cases

$$P_m=\cfrac{1.21\cdot E_T\cdot e_a^2}{R^2}$$

Theoretical elastic instability pressure for collapse of a perfect cylindrical, conical or spherical shell for testing load cases

$$P_{m_{test}}=\cfrac{1.21\cdot E_{T_{test}}\cdot e_a^2}{R^2}$$

Radio $ P_m/P_y $

$$P_m/P_y=\cfrac{P_m}{P_y}$$

Radio $ P_{m_{test}}/P_{y_{test}} $

$$P_{m_{test}}/P_{y_{test}}=\cfrac{P_{m_{test}}}{P_{y_{test}}}$$

Radio $ P_r/P_y $

$\text{if }\ P_m/P_y<0.5$
$$P_r/P_y=0+\cfrac{0.09-0}{0.5-0}\cdot\left(P_m/P_y-0\right)$$
$\text{else if }\ P_m/P_y<1$
$$P_r/P_y=0.09+\cfrac{0.18-0.09}{1-0.5}\cdot\left(P_m/P_y-0.5\right)$$
$\text{else if }\ P_m/P_y<1.5$
$$P_r/P_y=0.18+\cfrac{0.255-0.18}{1.5-1}\cdot\left(P_m/P_y-1\right)$$
$\text{else if }\ P_m/P_y<2$
$$P_r/P_y=0.255+\cfrac{0.324-0.255}{2-1.5}\cdot\left(P_m/P_y-1.5\right)$$
$\text{else if }\ P_m/P_y<2.5$
$$P_r/P_y=0.324+\cfrac{0.386-0.324}{2.5-2}\cdot\left(P_m/P_y-2\right)$$
$\text{else if }\ P_m/P_y<3$
$$P_r/P_y=0.386+\cfrac{0.435-0.386}{3-2.5}\cdot\left(P_m/P_y-2.5\right)$$
$\text{else if }\ P_m/P_y<3.5$
$$P_r/P_y=0.435+\cfrac{0.479-0.435}{3.5-3}\cdot\left(P_m/P_y-3\right)$$
$\text{else if }\ P_m/P_y<4$
$$P_r/P_y=0.479+\cfrac{0.51-0.479}{4-3.5}\cdot\left(P_m/P_y-3.5\right)$$
$\text{else if }\ P_m/P_y<4.5$
$$P_r/P_y=0.51+\cfrac{0.533-0.51}{4.5-4}\cdot\left(P_m/P_y-4\right)$$
$\text{else if }\ P_m/P_y<5$
$$P_r/P_y=0.533+\cfrac{0.548-0.533}{5-4.5}\cdot\left(P_m/P_y-4.5\right)$$
$\text{else if }\ P_m/P_y<5.5$
$$P_r/P_y=0.548+\cfrac{0.565-0.548}{5.5-5}\cdot\left(P_m/P_y-5\right)$$
$\text{else if }\ P_m/P_y<6$
$$P_r/P_y=0.565+\cfrac{0.567-0.565}{6-5.5}\cdot\left(P_m/P_y-5.5\right)$$
$\text{else if }\ P_m/P_y<6.5$
$$P_r/P_y=0.567+\cfrac{0.57-0.567}{6.5-6}\cdot\left(P_m/P_y-6\right)$$
$\text{else}$
$$P_r/P_y=0.57$$

$$P< \cfrac{P_r/P_y\cdot P_y}{1.5}$$

Radio $ P_{r_{test}}/P_{y_{test}} $

$\text{if }\ P_{m_{test}}/P_{y_{test}}<0.5$
$$P_{r_{test}}/P_{y_{test}}=0+\cfrac{0.09-0}{0.5-0}\cdot\left(P_{m_{test}}/P_{y_{test}}-0\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<1$
$$P_{r_{test}}/P_{y_{test}}=0.09+\cfrac{0.18-0.09}{1-0.5}\cdot\left(P_{m_{test}}/P_{y_{test}}-0.5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<1.5$
$$P_{r_{test}}/P_{y_{test}}=0.18+\cfrac{0.255-0.18}{1.5-1}\cdot\left(P_{m_{test}}/P_{y_{test}}-1\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<2$
$$P_{r_{test}}/P_{y_{test}}=0.255+\cfrac{0.324-0.255}{2-1.5}\cdot\left(P_{m_{test}}/P_{y_{test}}-1.5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<2.5$
$$P_{r_{test}}/P_{y_{test}}=0.324+\cfrac{0.386-0.324}{2.5-2}\cdot\left(P_{m_{test}}/P_{y_{test}}-2\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<3$
$$P_{r_{test}}/P_{y_{test}}=0.386+\cfrac{0.435-0.386}{3-2.5}\cdot\left(P_{m_{test}}/P_{y_{test}}-2.5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<3.5$
$$P_{r_{test}}/P_{y_{test}}=0.435+\cfrac{0.479-0.435}{3.5-3}\cdot\left(P_{m_{test}}/P_{y_{test}}-3\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<4$
$$P_{r_{test}}/P_{y_{test}}=0.479+\cfrac{0.51-0.479}{4-3.5}\cdot\left(P_{m_{test}}/P_{y_{test}}-3.5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<4.5$
$$P_{r_{test}}/P_{y_{test}}=0.51+\cfrac{0.533-0.51}{4.5-4}\cdot\left(P_{m_{test}}/P_{y_{test}}-4\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<5$
$$P_{r_{test}}/P_{y_{test}}=0.533+\cfrac{0.548-0.533}{5-4.5}\cdot\left(P_{m_{test}}/P_{y_{test}}-4.5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<5.5$
$$P_{r_{test}}/P_{y_{test}}=0.548+\cfrac{0.565-0.548}{5.5-5}\cdot\left(P_{m_{test}}/P_{y_{test}}-5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<6$
$$P_{r_{test}}/P_{y_{test}}=0.565+\cfrac{0.567-0.565}{6-5.5}\cdot\left(P_{m_{test}}/P_{y_{test}}-5.5\right)$$
$\text{else if }\ P_{m_{test}}/P_{y_{test}}<6.5$
$$P_{r_{test}}/P_{y_{test}}=0.567+\cfrac{0.57-0.567}{6.5-6}\cdot\left(P_{m_{test}}/P_{y_{test}}-6\right)$$
$\text{else}$
$$P_{r_{test}}/P_{y_{test}}=0.57$$

$$P_{test}< \cfrac{P_{r_{test}}/P_{y_{test}}\cdot P_{y_{test}}}{1.1}$$