COMPLEX STRESS DISTRIBUTIONS IN ENGINEERING MATERIALS. 291 
On Certain of the More Complex Stress Distributions in 
Engineering Materials.—Report of Committee (Prof. HE. G. 
Coxer, Chairman; Profs. L. N. G. Fron and A. Roserrson, 
Secretaries; Prof. A. Barr, Dr. C. Curez, Dr. Grtpert Cook, 
Prof. W. E. Daupy, Sir J. A. Ewrna, Mr. A. R. Fuuton, Mr. J. J. 
Guest, Dr. B. P. Haieu, Profs. Sir J. B. Henperson, C. EH. 
Incuis, F. C. Lea, A. BE. H. Love, and W. Mason, Sir J. E. 
Petavet, Dr. F. Kocsrs, Dr. W. A. Scostz, Mr. R. V. SourH- 
WELL, Dr. T, E. Sranron, Mr. C. E. Srromeyer, Mr. J. S. 
Winson. 
Introduction. 
Tur Committee submit as their Report the following contributions embodying : 
(1) A review of recent advances in the special domains of (a) Stress Concentra- 
tions, (6) the Theory of Plane Stress in perforated plates ; (2) special researches 
carried out by members of the Committee during the past year; (3) an account 
by Prof. B. P. Haigh of his theory of failure of elasticity. 
I. Stress Concentrations due to Notches and like Discontinuities. By Prof. 
E. G. Coker, F.R.S., and Dr. Paul Heymans. 
II. The Distribution of Stress in a Flanged Pipe. By Prof. Gilbert Cook, D.Sc. 
III. On Stresses in Multiply-connected Plates. By Prof. L. N. G. Filon, 
F.R.S. 
IV. Stress Concentrations in Theory and Practice. By A. R. Griffith, M.Eng. 
V. The Strain Energy Function and the Elastic Limit. By Prof. B. P. Haigh, 
D.Sec., M.B.E. 
VI. Alternating Combined Stress Experiments. By W. Mason, D.Sc., and 
W. J. Delaney, B.Eng. 
VII. On some Problems relating to the Design of High-speed Discs. By 
R. V. Southwell, M.A. 
VIII. On the Stability of a Rotating Shaft, subjected simultaneously to End 
Thrust and Twist. By R. V. Southwell, M.A., and Barbara S. Gough. 
1X. The Stresses in Cylinders and Pipes with Eccentric Bore. By G. B. 
Jeffery, M.A., D.Sc. 
The Committee ask for re-appointment, with a grant of 1001. 
I. 
Stress Concentrations due to Notches and Like Discontinuities. 
By Prof. E. G. Coxsr, F.#.S., and Dr. Paut Hrymans, 
University College, London. 
Ir is well known that discontinuities in loaded members cause, in general, 
severe stresses in their neighbourhood, and therefore do not allow full economy 
of material to be realised in cases where such discontinuities are inevitable in 
practical construction. In the majority of such cases it is difficult and some- 
times impossible to calculate the maximum stresses produced, and experience 
in the behaviour of similar members is then usually relied on, in the absence 
of an accurate knowledge of the stress distribution which exists. The stress 
distribution caused by discontinuities has also become of importance in recent 
years in the testing of materials, and a considerable field of inquiry has 
developed on the behaviour of materials subjected to impulsive loads, which 
produce stresses at definitely shaped discontinuities sufficient to cause rupture 
at the chosen section, and in this way a classification of materials is obtained 
which has proved of great value in engineering practice, although with our 
present knowledge such testing operations can only be regarded as of an 
empirical nature. 
