Figure 28. Testing the segmented-wall 

 cylinder to failure; (a) test 

 arrangement, (b) cylinder 

 after failure. 



Second, the segmented-wall 

 construction, consisting of small 

 segment modules held together with 

 shear pins, is a feasible m'ethod of 

 assembling cylindrical pressure 

 vessels where the axial forces on the 

 end closures are not resisted by the 

 cylinder but by other structural 

 members. This construction method 

 appears to be desirable, however, 

 only for those applications where 

 stacked-ring construction is not 

 feasible because the dimensions 

 of the ring exceed the fabrication 

 capability of the industry. The 

 major drawback of this cylinder 

 construction technique is that it 

 requires approximately 9 to 1 

 times as much steel as the stacked- 

 ring construction method. In 

 addition, there is considerably more 

 machining required on individual 

 segments than on stacked rings, 

 but the increased amount of 

 machining is probably offset by 

 the mass-production techniques 

 that can be applied to their fabrica- 

 tion. From the stress analysis 

 viewpoint, the segmented-wall 

 construction presents also a real 

 problem not only because of the 

 magnitude of stress concentrations 

 at the shear-pin holes, but also 

 because this magnitude depends 

 to a large degree on the clearance 

 between the pin and the opening, 

 and on the alignment of the shear- 

 pin holes in successive segment layers. 

 Misalignment of holes between seg- 

 ment layers also can induce bending 

 strains in the shear pins causing them 

 to fail at lower internal pressure 

 loading than expected. 



34 



