Consider a semi-monocoque cylindrical pressure vessel with a diameter of 78 inches. The skin and stringers are made of the same material with an ultimate normal stress of 60,000 psi, an ultimate shear stress of 8,000 psi, and a Poisson's ratio of 0.3. We are using 10 identical stringers with the total area equal to 40% of the skin cross sectional area. For internal gauge pressure of 15 psi with yield factors of safty of 1.5 in tension and 2 in shear, determine:

- the pressure vessel's minimum skin thickness
- the cross sectional area of each stringer

EQUATIONS USED

SOLUTION

We find the skin thickness based on the stress allowables in the skin.

We will repeat the procedure based on the stress allowables in the stringer.

The minimum thickness is then found to be the one that does not violate any of the stress criteria

The area of each stringer is found using

To Section A16.5

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