Effects of Repair on Structural Integrity.

29774853PDFTech ReportDOT-VNTSC-FAA-93-11DOT-FAA-CT-93-79FuselagesAirframesFatigue (Mechanics)MaintenanceStatic loadsUnited States. Federal Aviation AdministrationRice, R.Francini, S.Rahman, M.Rosenfeld, M.Rust, Smith, S.Broek, D.Battelle Human Factors Transportation CenterJohn A. Volpe National Transportation Systems Center (U.S.)NTL-AVIATION-Aviation Safety/AirworthinessVolpe National Transportation Systems Center, Technical Reference CenterCommercial aircraft operators are required by FAA regulations to repair damaged aircraft structures. These repairs must be performed in a timely manner to reduce aircraft downtime and loss of revenue. A guiding principle that has been used for many aircraft structural repairs is to simply restore the structure to its original (or better) static strength and stiffness. However, fuselage repairs must withstand significant fatigue loadings and be damage tolerant if cracks do form in them. It must be understood where cracks are most likely to form so appropriate inspection procedures can be instituted. The report describes an effort undertaken by Battelle and funded by the FAA Technical Center via the Volpe National Transportation Systems Center (VNTSC) to address these issues. Since many repair stations and airlines do have at least basic computer facilities that can be used for fatigue and damage tolerance analysis, one goal has been the development of a relatively simple, yet accurate analytical tool to design aircraft repairs more effectively