Research Of Fatigue Damage In Aging Aircraft

It has been shown that the Widespread Fatigue Damage (WFD) can markedly affect the residual strength and the crack growth life of a structure with WFD. Based on existing researches on WFD in aging aircraft, this paper focuses emphasis on two questions. One question is the relationship between the relative depth of countersink and the fatigue life. And the other is the influence of a crack on one countersink on the fatigue life of other holes. According to the research results, the relative depth of countersink should be 1/3～2/3, thus can get the better fatigue life. A crack on one hole will cause the redistributing of stress, and this will decrease the resident strength and the crack growth life seriously. The aircraft's age statue of Air China, China Southern Airlines, and China Eastern Airlines has been investigated in this paper. Up to December, 2004, the average of civil aircraft of China is only 7.6, and this is very young. According to the investigation of fatigue damage, once the aging aircraft program is established and carried out strictly, these crack damage can be found out safely, and high airworthiness level can be kept.