Relaxation of Stress Concentration of a Crack by Stop Drilling Holes and Additional Holes and Its Practical Prediction
It is well known that a stress concentration of a crack can be relaxed by drilling a hole at the crack tip. The repair method is called a stop drilling procedure and often used to repair aircrafts, machines and so on. Then, when two additional holes are drilled near the stop drilling hole so as to face each other symmetrically, the stress concentration of the stop drilling hole can be relaxed further, and a fatigue life is extended. However, the size and the location of the additional hole suitable for repairing the fatigue damage are not clarified yet. In this paper, finite element simulations were performed on various plates containing the small center crack at which the stop drilling holes and the additional holes were drilled, and influences of the additional hole on the relaxation effect of the stress concentration of the stop drilling hole were investigated. Then, the size and the location of such additional hole that the stress concentration of the stop drilling hole is minimized were examined.
A. Saimoto and M.H. Aliabadi
T. Miyazaki "Relaxation of Stress Concentration of a Crack by Stop Drilling Holes and Additional Holes and Its Practical Prediction", Key Engineering Materials, Vols. 452-453, pp. 705-708, 2011