Prediction of aluminum alloy (AlMg6) lifetime under consecutive shock-wave and gigacycle fatigue loads

We investigated the influence of consecutive shock-wave and gigacycle fatigue loads on the lifetime of aluminum-magnesium alloy AlMg6. An experimental methodology for estimating the ultra-high cycle lifetime has been developed with reference to the situation of accidental high-speed collision of solid particles with fan blades and subsequent fatigue failure in the flight cycle conditions, common in the practice of aircraft engine operating. The test program for shock-wave loading of massive flat targets made of aluminum alloy AlMg6 with profiled impactors (explosive generator method) initiating controlled damage of various levels in the volume of the material was implemented experimentally, followed by the application of an ultra-high cycle load (the number of cycles 10₇–10⁹) on samples specially prepared from the target material samples. Fatigue tests of preloaded samples were conducted on Shimadzu USF-2000 ultrasonic fatigue testing machine.