General Instability & Critical Stresses in a Ring-Stiffened Perfectly Circular cylindrical Shell Under External Hydrostatic Pressure
"Kendrick I"
Rev. 0.0,
PROJECT GIVEN:
REQUIRED:
Find Critical Buckling pressures for mode shapes n = 2,3,4,5,6,7,8 for the given geometry and material. Also pressure case dry weight and wet weight.
1a)SHELL DIMENSIONS:
ID of Shell:
Inner Radius of Shell:
Mean Radius of Shell (a):
Sign Test
1b)FRAME DIMENSIONS:
Frame Total Height:
Test for Frame Ht.
Test = 1 is OK :
End Bay Length (each end):
Unsupported length of Shell (between frames)
2)MAT'L PROPERTIES:
6061-T6
Modulus of elasticity:
Material density:
Poisson's ratio:
Yield Stress:
Shear stress:
3) DESIGN DEPTH and PRESSURE:
Water density:
Number of pressure steps:
Pressure:
for buckling:
for stress:
SOLUTION:
Sectional Areas of Frame:
C.G. of Frame Section:
Radius of Centroid of Frame:
Eccentricity of the ring frame centroid from the mid-surface of the shell (POSITIVE INWARDS):
Second Moment of area of the ring frames' cross-section about its centroid and parallel to the axis of the cylinder (I):
Height of the Frame:
Radius to Frame:
Using a guess of the design pressure for the Critical pressure:
Lowest positive root is:
Margin of safety on buckling for:
Volume & Weight of Pressure Case:
Single Frame Vol.:
Cyl Vol.:
Weight of Case:
Weight Wet:
Materials
6061-T6
7075-76
Titanium (pure)
Titanium 6AL-4V
S.S. 17-4 ph
S.S. 316
Convert deg Rankine to deg Fahienheit
Convert deg Kelvin
Convert depth Meters to bar
Convert depth Meters to psig