Stachiw 



interior of the concrete hull away from penetrations are translated 

 into stresses, the measured stresses at locations remote from the 

 penetrations are found to be of the same magnitude as stresses de- 

 rived analytically for the interior of a thick sphere. 



The strains on the interior surface of the solid inserts varied 

 inversely with the modulus of elasticity of the particular insert 

 material (Figure- 15), Stresses, calculated on the basis of the 

 strains in insert materials, were higher than in concrete for materi- 

 als with modulus of elasticity higher than of concrete. Conversely, 

 the stresses in inserts with modulus of elasticity less than of 

 concrete, were less than in concrete itself (Figure 16). 



PHASE III 



CRITICAL PRESSURE OF OPERATIONAL HABITAT MODELS - The critical 

 pressures of the two identical habitat models were approximately 

 the same as of the concrete sphere with identical dimensions without 

 any penetrations (Table 5) even though one of the models was subject- 

 ed prior to destructive testing to its operational depth for 200 

 hours. 



Table 5. Implosion Pressures of Ocean Bottom Habitat Models 



STRAINS AND STRESSES IN HABITAT MODELS - The strains and 

 stresses in the interior of the concrete habitat models were not 

 significantly different from those found in spheres with solid 

 steel (E = 27 X 10^) or aluminum (E = 10 x 10" psi) inserts, even 

 though the rigidity of the annular steel penetration flanges was 

 approximately the same as of a rigid insert with a 5 x 106 psi 

 modulus of elasticity. The experimentally determined meridional 

 and equatorial stresses on the interior of the model were in the 



232 



