Figure F-3. Components of the top and bottom polar closures used in 

 NEMO capsules 1,2, and 3. 



The structural integrity test was performed on the steel parts in 

 conjunction with the structural integrity testing of the acrylic plastic cap- 

 sule, as it was felt that only by testing the steel closures mounted in the 

 acrylic plastic capsule (Figure F-4) would it be possible to obtain a realistic 

 evaluation for both. 



STRUCTURAL INTEGRITY CONTROL 



The overall structural integrity of the acrylic plastic capsules was 

 established by a hydrostatic proof test. The acrylic plastic capsules were 

 mated with their steel polar plates, instrumented with electric resistance 

 strain gages, and subjected to a 4-hour hydrostatic loading under 500-psi 

 external pressure. If no water was found in the interior of the capsule and 

 the strains measured at the equator matched those on prototype capsule 

 under identical loading (Figure F-5), the performance of the capsule was 

 acceptable. Since none of the three capsules leaked and the strains on the 

 equator matched those recorded previously on capsule 0, capsules 1 , 2, and 3 



211 



