Materials under Combined Stress. 



127 



Guest called these principal stresses P 1? P 2 , and P 3 , and 

 each represented the stress in a particular general direction, 

 irrespective of its relative magnitude. The notation has 

 been changed to P A , P B . and P c , because P l? P 2 , and P 3 have 

 been reserved to represent the principal stresses in descending 

 order of magnitude. 



C. A. Smith. 



'Engineering,' Aug. 20, 



1909. 



Table A. — Solid 

 Steel. 

 Combined Compressi 

 and Torsion. 



Max. 



Principal 



Stress. 

 lbs. s. m. 



19800 

 19800 

 2G100 

 29500 

 32300 

 34900 

 30500 



Max. 



Shear 



Stress. 



lbs./s. in 



19500 

 19500 

 20000 

 20400 

 20400 

 19900 

 18900 



Table C— 



Solid Mild 



Table D.- 



-Hollow 



Steel. 



Steel. 



Tension. Compression, 



Compression and 



and Torsion. 



Torsion. 



Max. 



Max. 



Max. 



Max. 



Principal 



Shear 



Principal 



Shear 



Stress. 



Stress. 



Stress. 



Stress. 



lbs./s. in. 



5. in, 



lbs./s. in. 



lbs./s. in. 



-20170 



19450 



24900 



23700 



-20560 



2! >42( ) 







-31810 



21000 



47600 



23800 



-.•'.1570 

 -35620 



2D70U 







1(810 







-38180 



19190 







-20750 



20610 







27950 



20320 







30140 



19710 







26370 



21 >5( H 1 







29050 



20421 1 







32300 



21300 







36420 



L8210 







205(H) 



20420 







- 19150 



19050 







-20210 



20320 







Guest's Steel Tube 



The maximum and minimum stresses for Guest's steel 

 tubes are plotted in fig, 5, and for his brass and copper tubes 

 in fig. 6 (PI. I.). Mean lines arc drawn through the points, 

 and their equations arc : — 



I. 

 II. 



III. 



IV. 



V. 



X. 



XI. 



XII. 



XIII. 



Guest's Copper Tube 



Guest's Brass Tube 



Px - 1-87 P 3 = 51400. 

 P 1 -0-92P 3 =58100. 

 Pi-1\L6P 3 =33500. 

 Pi -0-9 P 3 =42900. 

 P 1 ~0-93P 3 =33500. 

 Pi— 1'09P,=12700. 

 P, - 1*04 P 3 = 12400. 

 P x -1-Q3P 3 = 20100. 

 P, - 1-34 P 3 = 19000. 



