Figure D-5. Assembled 15-inch-diameter acrylic plastic capsule with equatorial ring. 



After pressurization of the capsule to implosion at 1 00°F , the 

 structural adequacy of the concept was to be inferred from a plot of implo- 

 sion pressure versus temperature generated by implosion testing at different 

 temperatures on an additional eight capsules with internal tie rods. Since the 

 critical-pressure-versus-temperature relationship appears to be linear in the 

 32 to 1 14°F test range, it would be easy to see whether the implosion 

 pressure of the equatorial ring capsule fit the linear relationship established 

 by the other capsules. A good fit would be a positive proof that the incor- 

 poration of the equatorial ring into the hull of the acrylic plastic capsule did 

 not introduce into the hull structure any stress raisers that decrease the 

 critical pressure of the acrylic plastic hull. 



FINDINGS 



When the capsule (Figure D-6) with the equatorial ring was pressurized 

 at a 100-psi/min rate to destruction at the ambient temperature of 100°F, it 

 imploded at 1 ,175 psi. This critical pressure was found to agree (Figure D-7) 

 with the value predicted for this temperature by the linear relationship estab- 

 lished by the implosion pressures of other capsules at different temperatures 

 (Figure 78). 



192 



