Equation (104) expresses the plastic buckling pressure p in terms of m 

 and n. Reynolds minimized this expression with respect to 4); that is, he 

 set aPp/94> - Oi 3.nd by devising a graphical scheme, he was able to obtain 

 the following convenient formula for the plastic buckling pressure: 



t 



%- 



£/hffe\ 



94> \R/ \ L / 



l_ict>(l-E /E ) 

 4 s' t 



3-24>(l-f ) 

 P 



(105) 



Figure 13 - Typical Stress -Strain Diagram Showing 

 the Various Modulii of Interest 



Before Equation (105) can be used, the secant and tangent modulii. 



which are defined on Figure 13, and are given, respectively, by 



da 



^ i ^ i 



E = ; E = 



s e ^ t d.£ , 



1 1 



:io6) 



69 



