Digital Repository, ICF12, Ottawa 2009

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Development and Validation of Fatigue Crack Growth and Lifing Methodologies Through Comprehensive Coupon and Component Testing Under Spectrum Loading Representative of P-3C
K. Walker, E. Matricciani, W. Hu, J. Duthie

Last modified: 2012-10-03


Fatigue crack growth analyses in support of structural integrity management for the Royal Australian Air Force (RAAF) P-3C maritime surveillance aircraft fleet are performed using the FASTRAN code developed by Newman. Based on previous coupon test program data, the crack growth analysis and inspection interval results are known to be conservative. Recent work by the P-3C manufacturer, Lockheed Martin, revealed some errors and shortcomings in the methods used to determine the sequence of loads and stresses at specific aircraft locations. Previous coupon and full scale testing were performed with load/stress sequences determined under the old load system, so it was considered important to conduct coupon and component testing under sequences accounting for the updated and more accurate loads. There is also a requirement to significantly improve the FASTRAN modelling to reduce the conservatism (while still remaining conservative), thereby extending inspection intervals, realising significant financial savings and improving aircraft availability. Coupon tests to quantify total life from natural crack formation and cold working effects, and sub-component tests replicating complex structure were also conducted. This paper summarises these various coupon and component test programs, and details the latest results with improvements in the FASTRAN modelling process

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