﻿Manchester Memoirs, Vol. xlix. (1905), No. 7. 



VII. Experiments on the Relation between Uniform 

 Compressive Stress and Permanent Strain in 

 Wrought Iron and Steel. 



By W. C. POPPLEWELL, M.Sc, A.M.InstC.E. 



( Communicated by Mr. Francis Jones, M.Sc, F.R.S.E.). 

 Received January 24th. Read February yth, igo£. 



In a Paper communicated to the Manchester Literary 

 and Philosophical Society in 1893, Dr. (then Mr.) T. E. 

 Stanton described a series of experiments for determining 

 the relation between tensile stress and the permanent 

 strain it produced in bars of wrought iron and steel. By 

 plotting the logarithms of the stresses and of the corre- 

 sponding strains, Dr. Stanton found that the relation was 

 given by an expression of the form — 



p=C . e h 



where/ is the stress on the bar, e the ratio of the elonga- 

 tion to the original length, and C and k constants varying 

 with the material tested. 



In 1899, Dr. G. Wilson communicated to this Society 

 the results of similar experiments on copper bars, 

 the relation following the same general law, but having 

 different values for the constants C and k. 



In order to see how far this same law holds for 

 compressive stresses and their permanent strains the 

 author carried out a number of tests at the York- 

 shire College in 1899 upon bars of steel, wrought iron, 

 copper, gun metal, and aluminium, and found that the 

 law is sensibly the same for compression as for tension. 



March 24th, igo$. 



