COMPLEX STRESS DISTRIBUTIONS IN ENGINEERING MATERIALS. 201 
(equal + alternations of stress) are a ‘ reflection ’ of the yield point or elastic 
limit, giving figures in support—a contention not borne out by nearly all 
other tests. 
The effect upon resistance to fatigue of microscopic ‘ rods’ of manganese 
sulphide is shown; tests being made with stresses parallel and also per- 
pendicular to the length of the ‘ rods.’ 
4 Bairstow, L. 1909 Elastic Limits of Iron and Steel under Cyclical Varia- 
tions of Stress. ‘Phil. Trans. Roy. Soc.,’ 210, 
Dec. 9, 1909. 
This paper is a very important contribution to the subject of alternating 
stress. The author has thrown much light on the strain history of the 
Wohler test on iron and steel, and has revealed the nature of the stress- 
strain relations, whether of hysteresis or permanent extension, throughout 
his tests. The main conclusions are mentioned in various places in the 
Report, and only one or two salient facts need be mentioned here. He has 
proved the existence of elastic ranges of stress which were suggested by 
Bauschinger as the explanation of Wohler’s results ; and from comparison 
of these elastic ranges (ranges for which the hysteresis loop disappears), 
with the safe limiting ranges found by Wohler for presumably similar mate- 
rial, he has concluded that the former are identical with the latter. 
Work (previous to Bairstow’s) on the points just mentioned is con- 
tained in No. 7, Bauschinger; No. 82, Stanton and Bairstow. See also 
Unwin’s ‘ Testing of Materials,’ Article 253, edition 1910. 
5 Baker, E. 1905 Report of Tests of Metals. Abstract in ‘Iron and 
Steel Inst. Journ.,’ 1905, IT., p. 768. 
Tests of material at the Watertown Arsenal. Re-tests made of wrought 
iron, following a period of rest of twenty-two years, showing that certain 
tensile properties characteristic of the early overstraining still remain in the 
iron. 
6 Baker, Sir E. 1886 Influence on Steel of repeated subjection to Stress. 
‘Proc. Inst. Civil Engineers,’ cxxiii. See Unwin’s 
‘Testing of Materials.’ 
7 Bauschinger, J. 1886 Ueber die Verinderung der Elasticitiétsgrenze und 
Festigkeit des Eisen, ete. ‘ Mitthlg. aus dem Mechan- 
ischtechnischen Laboratorium in Minchen.’ See 
Unwin’s ‘ Testing of Materials,’ also for Bauschinger’s 
earlier paper. 
8 Berger, Karl 1899 Elasticity of Cast Iron subjected to repeated tensile 
and Compressive Strain. See Abstract in ‘ Proc. 
Inst. Civil Engs.,’ exxxvi. 370. 
No particular value can be assigned for the elastic strain due to a definite 
load, since this strain depends upon previous loadings. See No. 9. 
9 Berliner, S. 1906 Behaviour of Cast Iron under slowly Alternating Stress. 
‘Ann. de Physique,’ 20, 3, June 1906. ‘Sc. Abs.,’ 
1906, No. 1528. 
Investigation of the amount of strain after successive loadings of cast 
iron in equal tension and compression +p’. An expression is given for the 
strain at any stress p, after such loadings, in terms of p and p’. Similar 
work for + torsion of cast iron. See No. 8. 
10 Blount, B. 1910 Tensile, Impact Tensile, and Repeated Bending Tests 
Kirkaldy, W. G. of Steel. ‘Inst. Mech. Engs. Proc.,’ 2, 1910. ‘Sci. 
Sankey, H. R. Abs.,’ A, 300, 1911. 
In the repeated stress tests the specimen is bent to and fro in a machine 
worked by hand. The angle of bending on either side is 464°, and a very 
few cycles break the specimen. The work done is automatically recorded 
and is found to be a measure of the ductility. See No. 3. 
11 Bouasse, H., and 1908 Decay of Oscillations. ‘Sci. Abs.,’ 1908, No. 1225. 
Carriére, L. ‘ Annal. Chem. Phys.,’ 14, June 1908, also ‘ Annal. 
Chem. Phys.,’ 2, May 1904. 
See Report, Appendix I. 
