A.P. Berens, C.A. Babish, J.P. Gallagher

The damage tolerance philosophy is used by the United States Air Force (USAF) to ensure both the safety and durability of aircraft structure against damage (fatigue, corrosion, impact, etc.). The timing of fatigue driven maintenance actions based on design stresses and deterministic bounds on equivalent fatigue damage has proven effective early in the life of a structure. However, there are many stochastic damage drivers in an aging fleet that result in populations of crack sizes at critical locations. An assumption of an upper bound to characterize the potential fatigue damage growth behavior in a fleet is not necessarily a tenable assumption in aging fleets. Further, consideration of only the critical crack size may not lead to the optimum maintenance schedule for minimizing costs. Accordingly, to account for the random nature of fatigue damage in aging aircraft, structural risk analysis is being introduced as another decision making tool to support the planning of maintenance actions. The USAF has developed and used a structural risk analysis program, entitled PRobability Of Failure (PROF), that synthesizes the hazard rate and probability of fatigue failure as a function of flight hours based on data largely available from the USAF Aircraft Structural Integrity Program (ASIP). This paper presents the PROF approach to the calculation of these risk characterizations. The analysis is demonstrated using representative DTA data and crack size distributions determined from cracks detected during routine inspections. Emphasis is placed on communicating the failure probability results in terms amenable to decision makers.

23rd ICAF Symposium of the international Committee on Aeronautical Fatique, 2005, Hamburg

Conference Paper

englisch

A5, 12 Seiten

DGLR-Bericht, 2005, 2005-03, 23rd ICAF Symposium of the international Committee on Aeronautical Fatique - Proceedings; S.125-136; 2005; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

maintenance, risk, aircraft aging, fatigue, planning

Bestellbar

2005