depths under consideration. A configuration analysis of the load module was 

 also required to compare all possible deployment concepts. A detailed 

 investigation of the hydrodynamic phenomena influencing the submerged 

 station was necessary to establish methods of deployment and recovery. 



Pressure hulls for in-situ plants would be constructed in a manner 

 similar to existing submersible hulls. The only two pressure hull shapes 

 worthy of consideration for the depths under study are the sphere and the 

 cylinder. The shape selected depends on both the mission definition and 

 efficient space utilization. Relative volume effectiveness of the two shapes 

 is 53% for spheres, 59% for horizontal cylinders, and 93% for vertical 

 cylinders. 



Pressure Vessel Analysis. There are two modes of failure which must 

 be considered for thin shells subjected to external pressures; collapse by 

 yielding and collapse by buckling. Minimum factors of safety applied to 

 these failure modes were established at 1 .5 and 2.0, respectively, with local 

 stresses limited to 3/4 of the yield stress at operating depth. 



The following equation was used for computing the collapse of spheres 

 by yielding:* 



2hCT„ 



The basic equation used for computing the collapse of spheres by buckling 

 was 



P., = o.86^fi;i; (^y 



or for elastic buckling 



Pcb = 0.84 E 



(rlo) 



where E = modulus of elasticity 



Eg = secant hnodulus of elasticity 



E-p = tangent modulus of elasticity 



h = shell thickness, in. 



The reader is referred to the list of symbols on the foldout page at the end of this 

 report. 



