Comparison of Analytical Crack Growth Modelling and the A-4 Wing Test Experimental Results for a Fatigue Crack in an F-111 Wing Pivot Fitting Fuel Flow Hole Number 58.
AERONAUTICAL AND MARITIME RESEARCH LAB MELBOURNE (AUSTRALIA)
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This report details a series of analyses which were performed to develop expertise and evaluate the performance of several fatigue crack growth prediction computer codes. The analyses were performed for the case of a fatigue crack in the lower plate of the F-111 Wing Pivot Fitting, adjacent to Fuel Flow Hole No 58. This location is a known fatigue critical location and is designated as DI 86. Fatigue cracking leading to failure occurred at this location on the A-4 wing full scale fatigue test after approximately 12,200 hours of testing. An experimentally derived crack growth curve was available from the A-4 wing test. Analytical models were developed using conventional LEFM software codes FractuREsearch and AFGROW and the analytical crack closure code, FASTRAN II. The analysis results were compared with the experimental result and also with the analysis originally performed by the manufacturer, General Dynamics. Consistent with previous work, the analytical crack closure code, FASTRAN II, produced the most consistent and accurate results.