——_—- = ee 
ee srr TT 
ee ne 
COMPLEX STRESS DISTRIBUTIONS IN ENGINEERING MATERIALS. 9337 
In the ‘ preliminary dead-weight tests’ of A6, B24, A9, B17, De — 2, and 
Ge 
we obtain the following values of G 
56 _ 66 
7 =< eto 
For A6 G X a5 “eo 
E 49 _ 66 
o 9. —9yx =o 9 
Bor Bd4 = 2X 75 X gg = 48 
For Ag 2 = 2x 1? x 86 _ 9.59 
C 59 ~ 62 
r E 68 66 
For B17= = 2x 6 _ 9-43 
re 6 595 62 
giving a mean value for = of 2.48, which, incidentally, makes Poisson’s Ratio 
=0.24. 
Assuming E to be 30x10® lb. per sq. in., this ratio of E to C makes 
C=12.1x 108. 
For specimen B24, which happens to have the mean of the above values of * 
x —-—_— =0°100 
Y bending __ 660 8°54 x 2240 
Phebe 3) 42° 30x 108 
Taking any test in bending, let R (cm.) be any range of strain, elastic or 
otherwise, then strain corresponding to R 
ar 
1 660° 
and substituting the value off for the specimen from equation (1), we have 
this strain 
—Pe 660 R_ppey 2240 
E R, 660. BR, 30x10° 
a Rabe S74 19. oot Wil Weer ay 
eRo 
For any test in Torsion, the greater principal strain corresponding to a range 
of strain R (cm.) 
R _q,620 R 
=R4e x9:27x 107° aoa a ot a ee a ©) 
e=ur. 
The strains given by formule (3) and (4) will be exact if the following assump- 
tions are valid :— 
(1) that E and C are the same for the material of all the specimens, and 
that E=30x10%lb./Q]’; 
(2) that the fillets connecting the parallel part with shoulders of a specimen 
have, in that specimen, the same proportional effect on both bending and 
twisting strains and stresses; 
(3) that the strains have a linear distribution from axis outwards. 
Using formule (3) and (4), the greater principal strains and the greatest 
strain difference have been worked out, and set forth in Table V., for the 
separately applied bending and twisting tests previously done. 
