material was not a good substitu- 

 tion. Figure B-16 shows that 

 specimen 5-2 had a very local 

 failure at the top edge which was a 

 bearing-type failure. 



Boundary behavior is quanti- 

 fied in Table B-4. For conveni- 

 ence, a nondimensional value, 4), 

 was selected to express boundary 

 behavior as the ratio of radial 

 displacement at the end supports to 

 the radial displacement at midlength 

 of the specimen. A rigid support 

 would be identified by (}) = and a 

 free support by (]) = 1 . 



Observed boundary perfor- 

 mances showed a small difference 

 between actual and theoretical 

 behavior. For free- support speci- 

 mens the ideal 4) of 1.00 was closely 

 approximated. Two specimens with 

 t/D = 0.037 showed free-support 

 behavior where (^ was 0.90 and 

 0.96. Specimen 2-3 showed unusual 

 behavior where the bottom of the 

 cylinder moved radially inward the 

 least, ^ = 0.60, but the top moved 

 inward the most, (|) = 1.36 (i.e., 

 the top of the cylinder at the flat 

 spot location moved inward more 

 than the middle) . 



Figure B-12. Fragments of failure 

 hole from specimen 2-2. 



Figure B-13. Post-implosion view of 

 specimen 3-1 (t/D^ = 0.037, sim- 

 ple support). 



60 



