Conclusions. From an operational standpoint, the separated layer 

 vessel is more complex than other concepts studied, because of the annular 

 space pressurization required. Fabrication, which requires fairly extensive 

 welding, would be more costly and less reliable than fabrication of vessels 

 requiring less welding. The stresses are controlled by the annular space pres- 

 sures as well as the test chamber pressure so that the stressing of the vessels 

 may be made to suit the individual test pressure. This concept merits further 

 study for use in larger pressure vessels. 



Recommendations. It is recommended that further studies be made 

 of the problems associated with the separated layer pressure vessels, namely, 

 deformation of the vessels under pressure, effect of implosions or other dynamic 

 disturbances including the possibility of buckling of the inner vessel, stresses 

 in the vessels near the end flanges, burst strength, etc. 



In view of the above-mentioned uncertainties, the separated layer vessel 

 concept is not recommended for the 10-foot-diameter, 10,000-psi pressure 

 vessel under immediate consideration. 



precom pressed thick steel liner 

 pretensioned wire 



WZZZZZ^Z. 



+ o I 

 R_ R. R, 



R. k 

 I 



unpressurized pressurized 

 Distribution of Hoop Stress 



Figure A-4. Pretensioned-wrapped-wire 

 concept of pressure vessel 

 construction. 



Wire-Wound, Cylindrical Steel-Core 

 Vessel 



The concept of wire-wound 

 cylindrical steel-core vessels sub- 

 jected to high internal pressures has 

 been used for reinforcing gun barrels 

 (Figure A-4), in which the wire 

 windings are used only for absorbing 

 hoop and radial stresses. The wind- 

 ings offer no resistance to axial loads 

 and an inner monobloc or multilayer 

 steel core must be used to absorb 

 the axial internal-pressure load, or an 

 outer yoke must be employed for 

 the same purpose. 



In the absence of internal 

 pressure, the windings exert an 

 external pressure on the core which 

 results in compressive stresses in the 

 core. Internal pressures then act 

 to induce hoop-tension stresses in 

 both the inner monobloc and its 



47 



