280 REPORTS ON THE STATE OP SCIENCE. — ^1916. 



Stress Distributions in Engineering Materials. — Interim Report 

 of the Committee, consisting of Professor J. Perry (Chair- 

 man), Professors E. G. Coker and J. E. Petavel (Secre- 

 taries), Professor A. Barr, Dr. C. Chreb, Mr. Gilbert Cook, 

 Professor W. E. Dalby, Sir J. A. Ewing, Professor 

 L. N. G. FiLON, Messrs. A. E. Fulton and J. J. Guest, 

 Professors J. B. Henderson, F. C. Lea, and A. E. H. 

 Love, Dr. W. Mason, Dr. F. Eogers, Mr. W. A. Scoble, 

 Dr. T. E. Stanton, Mr. C. E. Stromeyer, and Mr. J. S. 

 Wilson, to report on certain of the more Complex Stress 

 Distributions in Engineering Materials. 



[Plate III.] 

 During the past year the time of the various members of the Committee 

 has been, to a large extent, taken up by work in connection with the war, 

 and some of the researches carried out by Professor Coker and others, 

 although having a direct bearing on the work of the Committee, cannot, 

 at present, be included in the report. 



Papers have been received from Mr. Stromeyer, Dr. Stanton, and 

 Dr. Mason, and are published as appendices. 



Mr. Stromeyer submits results of tests in tension, compression, and 

 tension and shear made on a number of steels of different compositions. 



Dr. Mason has carried out some experiments with the alternating 

 stress machine he recently designed ; these show that when the range of 

 cyclic strain in alternating bending or in alternating torsion is not entirely 

 elastic, the range of non-elastic strain varies largely with change of fre- 

 quency of cycle. Some experiments have been made to investigate the 

 recovery or apparent recovery that takes place when a piece showing 

 ' cyclical permanent set ' is allowed to rest. Similar ' recovery ' has 

 been found, under certain circumstances, after alteration of frequency 

 of cycle, during tests wherein the range of stress was constant throughout. 



Dr. Stanton gives a description of a new machine for tests of materials 

 in combined bending and torsion. 



The general result of his work is a confirmation of Guest's hypothesis 

 for the material used. 



The Committee ask for reappointment with a grant of 801. 



Appendix I. 



An Experimental Comparison of Simple and Compound Stresses. 



By C. E. Stromeyer. 



The following experiments were carried out on twenty-six samples 

 of mild steel of which the chemical analyses and many mechanical tests 

 have been previously reported. Vide ' Journal Iron and Steel Inst.' 1907 I., 

 1907 III., 1909 I. ; 'Proceedings R.S.,' 1915; ' Trans. Inst. Naval Archi- 

 tects,' 1915. 



The object of the present set of experiments was in part to trace a 

 relationship between tension, compression, and shear stresses, in order 



