Abstract
A closed form solution of the Stress Intensity Factor (SIF) for stiffened flat sheets, typically used in aircraft construction, in Multiple Site Damage (MSD) conditions, has been developed. The well-known theory of complex variable functions has been used, through the application of functions specifically developed for the case of cracks equally spaced and of equal length. Moreover, the superposition principle has been applied to evaluate the compression loads transmitted by the stringers through the rivets, by imposing the equilibrium on the crack free surfaces and the compatibility of displacements between sheet and stringers at the rivets location. The results have been compared with solutions available in the literature, obtained by combination of various analytical techniques and experimental methodologies, showing a good agreement. The proposed method is a reference for the validation of other numerical or analytical methods and effectively can replace the Finite Element Method for simple geometries.
Highlights
In 1988, an Aloha Airlines Boeing 737 lost a large portion of the fuselage when the aircraft reached its cruising altitude of 24,000 ft
The collapse was produced by the simultaneous presence of several cracks in a fuselage riveted joint (Multiple Site Damage: MSD)
The occurrence of Widespread Fatigue Damage (WFD), as in the case of the Aloha Airlines flight, poses a risk that the analyses can be invalidated over time due to the simultaneous presence of flaws within a structure
Summary
In 1988, an Aloha Airlines Boeing 737 lost a large portion of the fuselage when the aircraft reached its cruising altitude of 24,000 ft. The occurrence of Widespread Fatigue Damage (WFD), as in the case of the Aloha Airlines flight, poses a risk that the analyses can be invalidated over time due to the simultaneous presence of flaws within a structure. This problem produced the introduction of revised requirements to take into account in the fatigue life evaluation, among others, the effect of corrosion or repairs, as may happen in aging aircraft [3]. A sample calculation on a stiffened flat sheet was conducted, confirming the effectiveness of the results
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
