Local Stresses near Deep Surface Flaws under Cylindrical Bending Fields

Abstract
A series of tests was performed utilizing the stress freezing and slicing technique of photoelasticity in order to obtain the stress fields near points of maximum flaw penetration and where the crack border intersects the tensile surface of the plate for naturally grown surface flaws under fields of remote cylindrical bending. Geometries investigated ranged over crack depth to crack length ratios of approximately 0.13 to 0.55 and over crack depth to plate thickness ratios of approximately 0.27 to 0.79. Results were compared with several approximate theories on the basis of graphs of normalized maximum in-plane shear stress versus normalized distance from the crack tip and stress intensity factor in order to assess the validity of the several field theories. A numerical technique for data conditioning was employed from which the stress intensity factors were computed and compared with theoretical values.