fy=0,ox=0y=02=0 Gb Gb 2m(1-U)x2z(1-U)r For either edge or screw dislocation shear stress on slip plane along SD G edge dislocation n b screw dislocation nif y=0 , 0  x = y = z = r Gb x Gb xy 2 (1 ) 2 (1 )  − = − = For either edge or screw dislocation shear stress on slip plane along S.D.        − = = screw dislocatio n 2 edge dislocatio n 2 (1 ) s       G G r b  