き裂進展挙動に及ぼすき裂先端近傍への穴加工とその穴へのピンの打ち込みの影響について

概要

論文の詳細を見る
A technical method for retarding crack growth from pre-cracks by drilling holes in the vicinity of the crack tips was investigated. A series of fatigue crack growth tests were performed using double edge cracked specimen. In some specimens, holes were drilled in the vicinity of tips of pre-cracks. Also, calking pins were inserted into holes in some cases. The crack growth lives of drilled specimens were longer than those of specimens without holes. The longest fatigue life was observed in a case of specimen with the pins. Drilling holes and calking pins could change the growth direction of cracks, and then the coalescence of cracks, which grew from both edges, could be prevented. Also, it was considered that the compressive residual stress, which occurred by calking pins, was more effective to retard the crack growth than the reducing stress concentration around initial crack tips, which occurred by drilling holes. Therefore, it is concluded that calking pins into holes, which drilled in the vicinity of crack tips, is the effective method for retarding crack growth and for preventing coalescences of cracks.
2008-05-25