A crack-growth arresting technique in aluminum alloy

The purpose of the present study is to propose a new technical method for arresting crack initiation at stop-drilled holes by drilling ancillary holes following the making of the stop-drilled holes. The main idea of the method is to reduce the stress concentration at the edges of stop-drilled holes. To confirm the effectiveness of the method, analyses were performed by using software for two-dimensional elastic problems based on the body-force method, and some experiments were carried out. The calculation results show that the existence of ancillary holes effectively reduced the stress concentration at the edges of the stop-drilled holes. A close distance between the stop-drilled hole and the ancillary holes resulted in lower stress concentration at the edge of the stop-drilled hole. Also, a considerable reduction of stress concentration was obtained by arranging for the diameter of the ancillary holes to be larger than that of the stop-drilled holes. Consecutively, the experimental results showed that the fatigue initiation life was in good agreement with the calculation results.