^ split 

 shear 



^ split 

 shear 



segmented-wall module design is 

 only one-eighth to one-ninth of 

 a stacked-ring wall of equal internal 

 dimensions and overall weight. 

 However, because of the many 

 unknowns present, it is impossible 

 to postulate with reasonable 

 accuracy what the internal pressure 

 capability of such a vessel would 

 be without constructing a model 

 of it and pressurizing it to failure. 

 One further disadvantage 

 of a segmented-wall vessel is that 

 all the areas on modules and shear 

 pins where stress raisers may initiate 

 fracture cannot be inspected satis- 

 factorily without disassembly. Of 

 course, if the fracture does take 

 place, the failure of the vessel will 

 be local, similar to that of a stacked- 

 ring vessel and easily repaired. The 

 number of shrapnel fragments will 

 be somewhat larger than in the 

 stacked-ring vessel because each 

 module is a potential projectile, 

 but with proper precautions 

 (for example, placing the vessel in 

 a pit) this hazard can be virtually 

 eliminated. 



The construction of the 

 cylindrical portion of the pressure 

 vessel from modules permits the 

 assembly of the cylinder from 

 easily manufactured, transported, 

 and assembled segment modules. 

 This, however, does not make the 

 size of the segment module forging the sole factor limiting the cylinder's diam- 

 eter, for the end-closure retaining flanges and the end closure itself are generally 

 substantial forgings, similar to those found in the stacked-ring assembly vessel 

 and much larger than the individual segment module. Clearly, to eliminate the 

 forging of the end-closure retaining flange or of the end closure itself as the 

 factors limiting the vessel's size, it is necessary to make them modular also, or 



Figure 10. Concept of a pressure 

 vessel composed of a 

 segmented-wall cylinder, 

 segmented end-closure 

 retaining flange, modular 

 end closure and tie-rod 

 end-closure restraint. 



16 



