PLASTIC FAILURE OF CYLINDRICAL SHELLS. 



639 



23 



as in earlier tests. At 11,750 lb., which appeared to be the maximum 

 which could be reached, the load was removed to ensure that the jack was 

 working properly. Everything was found to be in order and on re-loading 

 the cylinder it was found impossible to increase that load of 11,7501b. 

 Plastic straining, however, continued for some time and ultimately a split 

 occurred In the shell ; the depth of dent was then 3-6 inches. That split 

 is seen at (b) in Figs 36, the contours being at intervals of 0-2 inch. The 

 load-deflexion curve, which is shown in Fig. 37, calls for no special com- 

 ment, as it is similar in its features to those obtained in earlier tests. The 



Fig. 38. 



JO 11 



ram displacement inches 



Load-Displacement Curve for 

 Cyunder No. 3. 



CoNTOCBS OF Dbht vs Cyltndeb No. 3. 



shortening of the cylinder is shown in Fig. 34, and the plotted contours in 

 Fig. 38. 



Two tests were made on the stiff-ended cylinder No. 11 and the load- 

 displacement curves for those are given in Fig. 39. In Test No. 11 A the 

 maximum load carried was practically identical with that in Test No. 3 on 

 a cylinder with normal ends, but the depth of dent produced was only 1-5 

 inch as compared with 3-6 inches. Failure occurred by a tensile fracture 

 of the skin as shown on the contour drawing of the final dent in Figs 40 

 and 41 (facing p. 17). At a loading of 11,100 lb. the overall shortening of 



