II. MATERIAL PROPERTIES 



The formed hemispherical head was made from 7079 -T6 aluminum, 

 and was machined to the final dimensions of Configuration A by the Hahn 

 and Clay Machine and Boiler Works*. Typical mechanical properties of 

 this material are as follows^ ^ )''"'': 



0-^ = 77 ksi 



or = 66 ksi 



Elongation in Z" = 4% minimum 



Brinell hardness number = 150, (500 kg load, 10 mm ball) 



T^ = 48 ksi 



cTg = 22 liisi, (Based on 5 X 10 cycles of reversed stress) 



E = 10. 4 X 10^ psi 

 A Pots son' s ratio of 3 3 was used in the stress computations for the aluminum. 



The plexiglass-'"'"'- port had the following mechanical properties'"^': 



Tensile Strength ASTM D-638-46T, 7 ksi 



1/4" specimen (0 2"/min) 



Flexural Strength ASTM D-790-45T, 12 ksi 



Span-depth ratio of 16(0, T'/min) 



Compressive Strength ASTM D-695-44T 12 ksi 



(0 2"/min) 



* 5100' Clinton Drive, Houston 20, Texas 



'•'■•• Superscripts in parenthesis pertain to the references given at the con- 

 clusion of the text 



Trade name of a methyl acrylate; available from the Rohm and Haas Co 

 Washington Square, Philadelphia 5, Pa 



