Main Pressure Vessel

Dimensions:

Material: Acrylic

Maximum Compressive Strength: 95 MPa

Radius: 5 inches

Length: 2 ft

Thickness: 1/8 ft

Hoop Stress vs Axial Stress

So the concern with the durability of the pressure vessel was that it would not hold under 80 feet of water. This is equivalent to 35 PSI under gauge pressure (As opposed to 49.7 psi in absolute pressure). Using calculations from Hibbeler,

σ=pr/t

where p is pressure, 

r is radius of the entire cylindrical enclosure

t is the thickness of the walls

σ = (35 lbf/in^2)*5 in/.125in

σ = 1400lb/in^2 = 1.4 ksi

1.4 ksi = 9.6 MPA

9.6 MPA << 95 MPA Compressive Strength

There is a safety factor of about 10 on the cylinder, which will be fine.

Citation: Hibbeler Statics and Mechanics of Materials, 3rd Edition. R.C. Hibbeler. 

Henry Quach

Goals

Background and strategic fit

Assumptions

Requirements

User interaction and design

Questions

Below is a list of questions to be addressed as a result of this requirements document:

Not Doing