Rectangular Tank

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Wall Plate Thickness Calculation

Tank Height, H = 1547 mm
Density, ρliquid = 1200 kg/m^3
Rectangular Tank Size: Width: 1067 mm Depth: 1547 mm Lenght: 1219 mm (Dimension is based on external surface of shell tank.)

Design Pressure: Positive (kPag ): Full of Water + 5
p' = 0.05 bar = 5 kPa
g = 9.81 m/s^2
E = 2.21E+02 GPa

Loading, q
The absoute pressure q at water depth of 1.574 m can be calulated as:
q = ρ g h + p'
   = (1200 kg/m^3) (9.81 m/s^2) (1.574 m) + (5000 Pa)
   = 23529.13 Pa
   = 23.52913 kPa
   = 0.02352913 MPa
0.02352913 MPa = 0.02352913 N/mm²

where
ρ = 1000 kg/m^3
g = 9.81 m/s^2



TABLE 11.4 Formulas for flat plates with straight boundaries and constant thickness
Case no., shape, and supports
1. Rectangular plate; all edges simply supported

R is the reaction force per unit length normal to the plate surface exerted by the boundary support on the edge of the plate.
E modulus of elasticity should also be specified in MPa and deflections output will be in mm. The modulus of elasticity of Carbon Steel is approximately 207 GPa = 207 x 10^9 Pa = 207 x 10^9 N/m^2.


As per Table 26 Case No.1a Chapter 10 of Roark's
Rectangular plate, all edges simply supported, with uniform loads over entire plate.
a = 305 mm
b = 387 mm
a/b = 0.7881
β = 0.2265
α = 0.0350
ɣ = 0.3310

At Center,
Maximum Deflection, δ
δ = -(α . q . b^4) / (E . t^3)
δ = -(0.0350 . q . b^4) / (E . t^3)
δ = -0.44
δ = 0.44 mm < t/2 then O.K

Maximum Bending stress, σ
σ = (β . q . b^2) / t^2
σ = (0.2265 x 0.02352913 x 387^2) / 6^2
σ = 22.17 MPa < σallowable 104 MPa. then OK
Material = SA 240 GR 316L
Yield Stress, σy = 157.0 MPa
Stress Ratio, σ/σy
σ/σy = 22.17 / 157
σ/σy = 0.14
At center of long side,
Maximum reaction force per unit length normal to the plate surface, R
R = ɣ . q . b
R = 0.3310 x 0.02352913 x 387
R = 16.97 lb/in
R = 1917.85 N/mm
R = 1917.8 5MPa

Plate Thickness = 6 mm is satisfactory











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