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2 PIPPABD AND CHITTY ON EXPERIMENTS ON THE 



" Experiments on the Plastic Failure of Cylindrical Shells." * 



By Professor Alfred John Sutton Pippard, M.B.E., D.Sc, M.I.C.E., 

 and Letitia Chitty, M.A. 



TABLE OF CONTENTS. 



PAOE 



Introduction 2 



Scope of the experiments 3 



Taylor's hypotliesis of distortion 3 



Test apparatus * 



Standard teat-cylinders 5 



Preliminary tests on steel and copper drums 6 



Tests on small cylinders 9 



Tests on large cylinders 18 



Energy absorption in plastic deformation 24 



Tests on stiffening rings 26 



Control tests on material 27 



Conclusions 28 



Acknowledgement 29 



Introduction. 



The work described in this Paper was carried out during the war in the 

 Civil Engineering Laboratories of the Imperial College of Science and 

 Technology for the Director of Scientific Research, Admiralty, to supple- 

 ment research into the behaviour of submarine hulls subjected to under- 

 water explosions. The explosive work was carried out elsewhere partly 

 on large scale specimens and partly on exactly similar models to those 

 described in this Paper. The object of the investigation was to study the 

 behaviour of cylindrical shells when loaded beyond the plastic range by 

 forces acting on a small area of the surface, and under certain specified 

 conditions of support. Those conditions were most satisfactorily repre- 

 sented by bedding the cylinders for half their depth in carefully sifted 

 sand, and with few exceptions the loads were applied through a ball or 

 spherical-ended ram. 



The experiments included static tests in a test frame, dynamic tests 

 by means of dropping weights, and a few tests under hydrostatic pressure 

 on a variety of specimens. Some of the results recorded were needed for 

 a specific purpose, but the whole series is presented here as a general 

 account of an experimental investigation which may be of value as a study 

 of the plastic behaviour of cylindrical shells. 



* Crown Copyright reserved. 



