Abstract
A new fatigue testing method was proposed by which fatigue cracks can be initiated and propagated in a film adhered to cover an elliptical through-hole in a base plate subjected to push-pull cyclic loads. This method was based on Eshelby's elastic inhomogeneity model. According to this model, when an inclusion in an isotropic infinite body is ellipsoidal in shape, the stress and the strain within the ellipsoidal inclusion are uniform. It follows from this that a film corresponding to the inclusion has a uniform stress at all points within it. Using this method of film fatigue testing, rolled iron films annealed at 873K and 1073K were fatigued with a stress ratio of R=0, and then the effects of the rolling direction and annealing temperature on crack initiation and propagation behavior were studied.
