12 Wilson, Failure of certain Cast Steel Dies. 



If the tube is in contact with the whole of the inner 

 face e' = e. By equating the total shearing stress over any 

 cylindrical section to T there results 

 -> T 



whilst from II. and III. 



m Tfia r^- 

 4Trr„E r-r - t\; 







a KfY r.rJ 



^-"^A+IAa^ 



2fr 15 25 ri- 



As the result of several experimental determinations 

 of E and fx for cast steel, given in Unwin's Strength of 



Materials, it may be taken that E=\}i. This is equi- 

 valent to making A = u or /; = -• 

 Therefore, putting 



and 



^f./Li6 32/- 16 (/r- i)/-"^" i6o(/!-- I) 16 /^--^-i J' 

 which is approximately, for the \-alues obtaining in practice, 

 T / /rlogk . 



