Akademik Veri Yönetim Sistemi
54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Boston, MA, Amerika Birleşik Devletleri, 8 - 11 Nisan 2013
The article presents two stage fatigue life prediction of a stiffened aircraft fuselage panel, subject to GAG pressure cycles, with a circumferential crack and a broken stringer in stage two. As a worst case scenario, it is assumed that double cracks start at the edge of a rivet hole both on the skin and the stringer simultaneously. The first stage involves the fatigue crack growth until the stringer is completely broken with the crack on the fuselage skin propagating. The first stage itself is treated in two sub-stages, and fatigue life prediction is performed by approximating the crack propagation process using the application defined models of AFGROW. It is shown that second stage, which starts after the stringer is completely is broken, stress intensity factor history, provided by the center through crack application defined model of AFGROW, has to be corrected to account for the broken stringer, and three dimensional effects such as bulging of the skin and panel curvature. For the second stage, a detailed three dimensional local finite element model of the fuselage skin with the broken stringer is prepared to calculate the variation of the normalized stress intensity factor with crack length. It is concluded that the skin curvature and bulging of the skin due to the internal pressure can have significant effect on the stress intensity factor and the fatigue life of the fuselage structure. It is also shown how fast the crack can propagate in stage two, after the stringer is completely broken, compared to stage one. © 2012 AIAA.