An all welded vertical cylindrical tank 24m in diameter by 15m high is

designed for storage of molasses(SG=1.5).Determine the minimum thickness of

the shell plate if the allowable stress of the plate is 140MPa and the welding

efficiency was 80%. Allow 1.6m free board for air space in the tank. Round off

your answer to whole number.

Guest Mar 28, 2022

#1**+2 **

It has been a while since I did these kind of calculations, but here is my stab at it :

140 MPa = 140 x 106 N/m^{2}

15 m - 1.6 m free board = 13.4 m high

Volume of the cylinder of molasses = pi r^{2 }h = pi (12)^{2} * 13.4 = 1929.6 pi m^{3}

mass of this volume 1929.6 pi m^{3} ( 1.5)(1000 kg/m^{3}) = 2 894 400 pi kg

Find stress using F_{s} = ma using mass above = 28 394 064 pi N

Now find the thickness ( if 100% weld efficiency)

F = stress * area where stress is 28 394 064 pi N area = pi d t = pi 24 t = 75.39822 t

140 x 10^6 N/m^{2} = 28 394 064 pi N * 75.398223 t m^{2}

solve for t = .0208155 m

Now factor in the 80% efficiency of the welds .0208155 m / .8 = .02601 m = ~~ 3 cm ( I think ! ~ EP )

ElectricPavlov Mar 28, 2022