ON STRESS DISTRIBUTION IN ENGINEERING MATERIALS. 



491 



lie between the lines representing constant maximum principal and tangen- 

 tial stresses, in the region occupied by the ellipses. 



The thin steel tubes employed in Guest's experiments being of moderately 

 high tensile material, with elastic-limits under simple tension from 15 to 

 27 tons per sq. in., it is inferred that the constant strain-energy hypothesis 

 is reasonably applicable for ordinary steels although their microstructional 

 features are too complex to admit of any complete theoretical treatment, 

 such as would be required to apply thermodynamic principles. 



Figure 18 shows, also, five experiments by Crawford^ on fiat steel plates 



08 



0^ 



a4 



02 



■02- 



I 



■06- 



.... Sted Tubes. J.J.Guest.mO 



• ••• Brass •> •• •> 



♦♦♦ Copptr - . » m\\3, 



-^ Steel Plates; W.J. Owrford, 1911. 

 ^(IJSS^nM^^^^ Tubes: R.G.C.BatsonJSn. 

 (2ion.EULimiU 



0-» Of 



IfOioJO 



Fig. 18. 



of circular profile, clamped at the edges and subjected to fluid pressure on 

 one side. Crawford concludes that, for such plates, de Saint Venant's 

 hypothesis (represented by the straight lines H V and H V for m = 2-5 and 

 3^) is more applicable than Kankine's hypothesis of constant maximum 

 principal stress. The value of m for these plates, experimentally deter- 

 mined, was 3- 19. As de Saint Venant's lines lie, in this part of the diagram.. 



» W. J. Crawford, Proc. R.S.Edin. (1911-12). 



