42 



THE NAVY OCEAN ENGINEERING PROGRAM 



Alumina has considerable potential on a strength-weight basis, but more 

 testing is required to determine its fatigue strength and corrosion resistance, 

 and to firmly estabhsh strength characteristics. The use of alumina, as in 

 the case of glass, depends upon the successful application of a proof test 

 to eliminate defective structures. 



GLASS AND REINFORCED PLASTICS 



Glass-Reinforced Plastics 



The Navy has been investigating glass-reinforced plastics for very deep 

 (greater than 15,000 ft) operating pressure hulls. As a result of this in- 

 vestigation the compressive strength of glass-reinforced plastics has in- 

 creased from approximately 75,000 psi in 1961 to over 200,000 psi at the 

 present time. This increase is attributed to improved fabrication and test- 

 ing techniques as well as to significant steps in improving the plastic matrix 

 material. 



Fiberglass reinforced plastic sphere, a recently developed low-density material 

 for use as auxiliary buoyancy in deep-submergence vehicles 



