Defense Technical Information Center Compilation Part Notice ADP 014084 TITLE : Recognition and Correction of Sonic Fatigue Damage in Fighter Aircraft DISTRIBUTION : Approved for public release , distribution unlimited
High performance aircraft that fly aggressive low altitude or high-angle of attack maneuvers will experience high acoustic loading, especially in the presence of external stores. These high acoustic loadscan lead to rapid sonic fatigue in thin gage metallic structure. As a means of prolonging fatigue life, while at the same time restoring structural load carrying capability in damaged structure, composite bonded repairs which incorporate damping layers have been developed. These damped composite bonded repairs are installed on F-15 flight test aircraft. This paper describes ways to recognize sonic fatigue damage, and the design and flight test results of represeintative damped patches.
Repair Substantiation for a Bonded Composite Repair to F111 Lower Wing Skin
This paper presents the results obtained to date as part of a comprehensive repair-substantiation program currently in progress for a safety-critical repair to an F-111 lower wing skin. From the viewpoint of demonstrating compliance with certification requirements, this F-111 repair represents the most technically challenging bonded repair undertaken to date by the RAAF. It is particularly significant that the repair was designed and implemented entirely by RAAF personnel, on the basis of design principles and application procedures developed by DSTO. This constitutes an important milestone in technology transfer from DSTO to the RAAF.The repair substantiation involves both detailed finite element (FE) stress analyses and structural testing at three levels, ranging from coupon-size specimens (representative bonded joints) to quasi- full-scale specimens representing a spar-stiffened wing-box structure. The close coupling of analysis and testing is shown to lead to a time- and cost-efficient certification package, with a confidence level comparable with full-scale structural testing.
Evangelical Law Firms and the Translation of Arguments: A study of the Evangelical Movement s Influence through National and International Courts
................................................................................................VII Acknowledgements......................................................................................IX Abbreviations............................................................................................XI Central Legal Terms .................................................................................XII