According to girder vibration theory of beam

"af"value

which is the product of blade tip vibration amplitude "a" and frequency "f"

was deduced to express vibration stress of blade. Based on the ultra-high cycle fatigue test result of a type of aero-engine compressor blade material specimen and "af" value theory

the blade high cycle fatigue life was deduced. The results of blade first order bending high cycle fatigue validated the deduction. It shows that when "af" value is 1700

1800

1900mm/s

the fatigue lives of ultra-high cycle fatigue test specimen and actual blade are in the vicinity of 1×107

0.7×107 and 0.5×107 cycle

indicating the fatigue life of ultra-high cycle fatigue test specimen is consistent with the actual blade.