applied fracture mechanics

218Applied Fracture MechanicsFigure 11. Component of the sum for the approximation criterion (32)Figure 12. Component of the sum for the approximation criterion (32a)S**n y iy i 11 .i1y i y (32a) i Both extremes of the Si function for both positive and negative values of are the minimashown in Fig. 12. Approximation criterion functions for (15), (20) and (32) (and theircomponents) as related to approximating values , for:- different approximated values yi equal to 5; 2; 1; 0.25; 0.01; 0.00001,- the same range of variability of , i.e. (-3yi, 3yi), in order to show the →0 effect, areshown in Fig. 13.