Determination of Stress Intensity Factor KI for a Three-Dimensional Crack Front by the Caustic Method

In this paper, an experimental technique to determine the stress intensity factor (SIF) KI for a three-dimensional crack front using the caustic method in combination with the stress-freezing and stress-releasing techniques is proposed. A comparison between the experimental results determined by the proposed method and the traditional photoelastic method is made; in addition, the experimental results of the present work are compared with the theoretical solution of Smith-Alavi. The experimental results obtained by the caustic method coincide favorably with the results obtained by the photoelastic method. The caustic method in combination with the stress-freezing and stress-releasing techniques proposed in the present work makes it possible to consecutively determine the distribution of the SIF KI for a three-dimensional crack front.