basic knowledge about submarines pressure hull and exostructure.

5. The Pressure
Hull The
Exostructure

6. Pressure
Hull
Shapes
Materials
Loading &
Calculations
Hull
Penetration
Structure
Classes
Presentation
topics

13. • Submarine pressure hull are usually made of steel, aluminum, titanium, acrylic
plastic and glass. However, the most widely used material is steel, because of a
high degree of knowledge available to designers and manufacturers as well as of
its outstanding performance in the ocean.
• Aluminum is generally considered unacceptable as a pressure hull material
because it is unwieldable and is subject to stress-corrosion cracking.
• Nevertheless one solution would be to bolt the hull together instead of welding
and anodize it to resist stress-corrosion cracking.
• Pure titanium is too susceptible to stress-corrosion at high tensile stress levels,
but titanium graphite alloys do not exhibit this problem.
• Despite of its weaknesses, such as its brittleness, high sensitivity to surface
abrasion, and considerable strength degradation at joints, glass and glass-
reinforced plastic has a low weight/displacement ratio.

23. Yielding of shell plate between two frames.

24. Second Mode Buckling (transverse view)

25. Shell buckling between frames

27. Total collapse of pressure
hull

29. Forms of failure of a submarine pressure hull.

31. Structural components of a submarine (transverse view)
Web Frames Ordinary Frames

33. Pressure hull penetrations
on the forward elliptical
bulkhead of a submarine

40. Exostructure
Materials
Loading
Types of
framing
Foundation
Outer Hull
Shells
Presentation
topics

47. Design Conditions
• Surfaced
• Submerged
• Launching and retrieval at sea
• Transport
• Towing
• Impact ( submerged )
• Bottom sitting
Design Loads
• Static weight of vehicle (gravity loads)
• Buoyancy loads
• Hydrodynamic force
• Sea slap (wave force) 500 psf
• Kinetic energy associated with impact force
• Propulsion and thruster force
• Equipment operating force
• Towing force

48. Exostructure
Framing
Framed
structure
Stiffened
shell
Combined
structure

52. Framing
Fairing panels & End
caps