Fretting loads on the surfaces of structural components can cause accelerated growth of short cracks. The rate of growth will depend on the combined stress intensity factor resulting from both remote and local loading. Many stress intensity factor solutions are available for remote loading, but solutions for arbitrary fretting loads are not readily accessible. In this paper accurate crack-line Green's functions are obtained from a boundary element analysis and then used to develop the Green's functions for loads on the edge of a half-plane containing a slant crack at various angles to the edge. These latter Green's functions can be used to obtain stress intensity factors for arbitrary stresses (normal or shear) on the edge of the half-plane without further stress analysis; simple integration procedures are all that is required.
NOMENCLATURE= boundaries of applied edge stress B, = coefficient defined in equation (30) 0, = coefficient defined in equation (33) E(t, I) = integral defined in equation (D7) Eo(r, I) =integral defined in equation (D12) f = force on crack (p or q ) F = force on sheet edge (P or Q) g = general crack-line Green's function gf, = specific crack-line Green's function G = general edge Green's function G$ = specific edge Green's function Z(m, I) = integral defined in equation (D5) Zk = integral defined in equation (C4) J,,, = integral defined in equation (19) J, = J, -J,,,,, (m = 0, 1 . . . No + 2) K; = stress intensity factor due to force on edge i = summation variable in equation (25), i = 0, 1,. . . , I K, KN = general stress intensity factor K;, K:, = stress intensity factors due to stress (n or T ) on edge I = summation variable in equation (27), 1 = 0,1, . . . , L L,, = integral defined in equation (A5) rn = summation variable in equation (30), m = 0, 1, . . . , M n = summation variable in equation (13), n = 0, 1, . . . , No N = I, opening mode; N = 11, sliding mode p f = coefficients of normal-force crack-line Green's function q: = coefficients of shear-force crack-line Green's function p , q = normal and shear forces on crack faces P, Q = normal and shear forces on edge of sheet 441 442 D. P. ROOICE et al. r = radial distance (r2 = x 2 + y 2 ) s,'= non-dimensional stress defined in equation (7) S l = integral defined by equation (1 7) Kf = integral defined by equation (1 7) x, = position of force on crack x, y = global Cartesian co-ordinates X = q / a y = lbll(lbl + a ) z = JI -zux sin 9 + U'X*
3%=s!-s!+2TL= T,F-T;,, 11, < = local Cartesian coordinates 9 = angle between crack and normal to edge p = Jb2 -2bq sin 9 + q 2 u = applied stress uo = normal stress constant u,= general stress at crack site a , = general stress on edge of half-plane u{ = stress at crack site in direction off due to force F on edge T = applied shear stress q, = shear stress constant