Stress Concentration - Concentration Factor For Cracks

Concentration Factor For Cracks

The maximum stress felt near a crack occurs in the area of lowest radius of curvature. In an elliptical crack of length and width, under an applied external stress, the stress at the ends of the major axes is given by:

where ρ is the radius of curvature of the crack tip. A stress concentration factor is the ratio of the highest stress to a reference stress of the gross cross-section. As the radius of curvature approaches zero, the maximum stress approaches infinity. Note that the stress concentration factor is a function of the geometry of a crack, and not of its size. These factors can be found in typical engineering reference materials to predict the stresses that could otherwise not be analyzed using strength of materials approaches. This is not to be confused with 'Stress Intensity Factor'.