PLASTIC FAILURE OF CYUNDRICAL SHELLS. 



643 



27 



Point loads were applied to the single ring by dead weights, the speci- 

 men being supported in a horizontal position on a lathe bed as shown in 

 Figs 44, Plate 1. 



The ring with its 2-inch attached shell was tested vertically in a 10-ton 

 Buckton testing machine as shown in Figs 45, Plate 2, lateral instability 

 being prevented by light guides which offered no restraint to movements 

 in the plane of the ring. 



Fig. 46. 



EXTENSION . PEB CENT 



Tensile Tests of the Matbbials Used foe the Ctllndee Sreixs. 



At successive loads the contours of the deformed rings were traced 

 directly on sheets of paper mounted behind the specimens and the results 

 are given in Figs 44, Plate 1, and Fig. 45, Plate 2. 



A feature of both of those tests is the evidence of two well-defined points 

 in each ring which suffered no radial displacement. These do not coincide 

 with the theoretically calculated positions of zero radial displacement for 

 elastic strains, the discrepancy apparently being due to a slight spread of 

 the horizontal diameter of the test rings which was assumed in the calcu- 

 lation to be completely restrained. This feature may be important in 

 simplifying an analytical treatment of the plastic distortion of rings. 



Control Tests on Material. 



Test specimens of the material used for the shell were provided by the 

 makers of the cylinders. The curves obtained in tensile tests on specimens 

 of 8-inch gauge-length are shown in Fig. 46. 



