PLASTIC FAILURE OF CYLINDRICAL SHELLS. 



641 



25 



Curves deduced from the dynamic teste on the small cylinders are also 

 shown in Fig. 42. Those specimens were deformed by balls of various 

 weights dropped from a height of 23 feet. The height of rebound was 

 deducted from that and the difference gave the efifective height of drop 

 which caused denting. These curves are also reasonably smooth, but the 



Fig. 42. 



DEPTH OF DENT : INCHES 



Ekeegy Absobbbd in Tests on Small Ctllndkes. 



energy required to produce a given dent is greater than when the dent is 

 produced by static dead loading in spite of the similarity of the deforma- 

 tions. This is consistent with the results of the tests on the steel cement 

 drum. 



Fig. 43 shows results obtained from static tests on the large cylinders. 

 These points also lie very fairly on a smooth curv« and explanatory notes 

 on the diagram indicate the main features. The higher point for No. 3 

 was estimated from the test curve obtained after the load was re-applied 

 and plastic strains allowed to develop until a tensile fracture occurred 

 (see p. 23). The energy absorbed when the maximum load was reached 

 and immediately before it was removed is given by the lower point for 



