Fatigue Crack Growth Prediction Under Spectrum Load Using Crack Driving Force △K~*

摘要

Fatigue crack growth behavior in D16 aluminum alloy under a fighter aircraft spectrum load sequence was determined by both experimental and analytical procedures. The prediction was performed using crack driving force parameter △K~*. The rms approach was used to approximate the spectrum sequence into an apparent CA load sequence, and the crack growth was predicted by a cycle-by-cycle approach. A fairly good correlation was obtained between the experimental and predicted results. The fatigue life prediction was conservative by this method, and the predicted fatigue life ratio N_(pred)/N_(expt) was about 0.86. The simple nature of the proposed prediction method and the reasonable accuracy in fatigue life prediction are quite encouraging. Further investigation comparing this method with a conventional method using a crack closure concept is underway and will be submitted for publication in the near future.