Investigators: Roland deWit and Richard J. Fields

Technical Description:

Sudden catastrophic failure of an aging aircraft may result from the linking up of corrosion and fatigue damage at rivet holes along the fuselage skin lap joint as occurred in a Boeing 737 operated by Aloha Airlines in 1988. To help the commercial aircraft and airline industries avoid these failures, a project was designed which would quantify the crack propagation process and mechanics of crack linkup at multiple site damage (MSD) for thin- sheet aluminum alloys which are prototypic of those used in airplane fuselage design.

Technical Objectives:

• The objective of this research project is to assist the aircraft industry by providing data for evaluating the possibility of sudden catastrophic failure of aging aircraft with short fatigue cracks emanating from rivet holes.

Anticipated Outcome:

• The major outcomes are expected to be the development of accurate calculations of the residual strength of an aluminum sheet containing multiple cracks and multiple site damage.

• The improved understanding of the cause of sudden catastrophic failure of aircraft that will result from this research will enable the commercial aircraft industry and the airline industry to design, operate, and maintain aircraft in a safer more cost effective manner.

Accomplishments for FY 1995:

• The experimental work was completed during the fiscal year.

• Three papers on this work were prepared and submitted for publication.

Impacts and Technical Highlights:

• The FAA Center of Excellence in Computational Modeling of Aircraft Structures at Georgia Institute of Technology is using the results of this work to develop a methodology to predict the residual strength of structures containing widespread fatigue damage.

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Last modified: Mon Jan 06 09:46:15 1997 Metallurgy Webmeister