A B S T R A C TStress intensity factors for an embedded elliptical crack approaching the free surface of the semi-infinite solid that is subjected to uniform tension perpendicular to the plane of crack are presented in a nondimensional form for various crack aspect ratios and crack distances from the free surface. Stress intensity factors are determined numerically using an alternating technique with two solutions. The first solution involves an elliptical crack in a solid and subjected to normal loading expressible in a polynomial of x and y. The second solution involves stresses in the half space due to prescribed normal and shear stresses on the surface. Effect of the Poisson's ratio on these stress intensity factors is also investigated. Stress intensity factors for a semi-elliptical surface crack in a finite thickness plate are then estimated in a nondimensional form for various crack aspect ratios and crack depth to plate thickness ratios.
Nomenclature~b suitable harmonic stress function = ~f= o ~ffi 0 ~ij; i+j < 3 2,/a, v ellipsoidal coordinates a semi-major axis of ellipse b semi-minor axis of ellipse h distance from the free surface to the center of ellipse or plate thickness X 2 y2 z2 co(s) 1 a2+s bZ+s s Q(s) s(a 2 + s)(b 2 + s) r/ Poisson's ratio G shear modulus u~ incomplete elliptic integral of the first l~ind K(k) complete elliptic integral of the first kind E(ul) incomplete elliptic integral of the second kind E(k) complete elliptic integral of the second kind snu. cnul, dnux, dcut, cdut, ndu~, ncul, sdu~ = Jacobian elliptic functions k, k' modulus and complimentary modulus of Jacobian elliptic functions, respectively 0 K~e with k 2 = (1 -b2/a 2)angle in the parametric equations of ellipse, x = a cos 0; y = b sin 0 90 °-0 i.e., x = a sin t, y = b cos fl opening mode stress intensity factor stress intensity factor for an elliptical crack embedded in an elastic solid