no 



0^ the plate, namely e and £ 



Taking ^v'^ " ^ ^'^^ experimental law 

 Investigations ty Lo<)e(l) and by 



must also be constant, 

 of plasticity wi 11 define the relat ionship between a ana /?. 

 Taylor and 0uinney(2) by different experimental methods jive results which are in good a-jreement 

 They have been expressed in terms of Lode's variables 



where O", , (T 



(1») 



principal stresses and strains and ct, > cr > ct,. 



The 



i.- I- y i.- i.- > 11} 



experimental relationsnip between /i and v is shown in Figure 10 of Taylor and Quinney's paper 



£7^ = 0. Since it will be found that ct > ct^ it is necessary to take ct as O", an3 £T as ct. , 

 3 yx •'x2yl 



this cass therefore 



/I = 2 a - 1 (20) 



Since the material ray be taken as incompressible to the Oejree of approximation here required 



and substituting this in Lode's variable V 



= 3i'/(/5+ 2) 



(21) 



(22) 



Some values of ^ and the corresponding experimental values of V taken from Figure 10 of Taylor 

 and 8uenney's paper are given in columns 1 and 3 of Table 1. The values of a from (20) are 

 given in column 2. Values of /3, found by using the values of V given in column 3 in (22), are 

 given in column 4. This experimental relationship between a and /5 is shown in Figure 1. 



TABLE 1. 



The 



