Fatigue Crack Growth in Aircraft Main Landing Gear Wheels
SourceFracture analysis of aircraft landing gear wheels under service-simulated operating loads using various fatigue crack growth characterization techniques is presented. Baseline constants for the wheel forging alloy 2014-T6 aluminum are established. The stress-intensity factors for a two-dimensional surface crack are developed using a proposed load model for the wheel's flange/bead seat radius. Crack growth predictions are performed using a modified crack growth (CRKGRO) program under spectrum load blocks. New stress-intensity factor subroutines for combined loads are added to the program library. The analytic results are compared with measured crack growth data during full-scale structural tests. Good agreement between analytic and structural test results was obtained, and a damage characteristic curve for the wheel flange is proposed. Qualitatively, fracture surface observations supported proposed crack-tip load models, state of stress, and crack growth data.