Abstract:

This paper, through research on damage value of fatigue load spectrum, finds out that the fatigue life of metallic material is linear with the damage value of fatigue test load spectrum, namely, the fatigue life of metallic material is linear with the weight of fatigue test load spectrum. Life factor can be deduced from the regularities, and the fatigue test time of full-scale component can be reduced from life factor. From what is displayed in the life factor of existing fatigue test data research, when adding damage value on the basis of average spectrum(fatigue damage value is 50%), 58.3% damage spectrum can reduce 11% of the full-scale component fatigue test time, 75% damage spectrum can reduce 36% and 91.5% damage spectrum can reduce 50%. It comes to the conclusion in this paper as follows:for the purpose of reducing full-scale fatigue test time, load spectrum enhancement is to be employed in full-scale fatigue test, which renders the life in load spectrum enhancement. Then the life factor of sample is used to revert it to the average life under average load spectrum. This average life is then divided by the standard fatigue dispersion coefficient, which renders service life. This method reduces the fatigue test time without violating the standard fatigue dispersion values, making the determination of aircraft life economical and reliable.

Key words: fatigue life, fatigue damage, life factor, average spectrum, heavy spectrum