Stress Intensity Factor at the Tip of the Crack as Influenced by Rivet Forces.

摘要

The effect of a riveted stiffener placed perpendicular to and in advance of a crack is twofold: first, the stiffener reduces the buckling of the plate containing the crack and second, rivet forces will be induced such that all rivets in the neighborhood of the crack tip will apply forces to the plate in a direction to oppose further motion of the crack. Both of these effects tend to stop the crack in the vicinity of the stiffener. In this report, experimental data is presented supporting the analytical study made in the previous Status Report. These test show that it is possible to measure K by use of strain-gages placed near the crack tip. Another test involves determination of K(sub c), the critical stress-intensity factor for onset of rapid fracture. Later tests investigate the effect of a single rivet force upon stress at the crack tip. Although the results of these tests are here summarized, this testing program is not complete.