Jixie qiangdu (Jan 2018)
ANALYSIS AND TEST OF COMBINED FATIGUE LOADING SYSTEM OF CERTAIN ENGINE FAN BLADE
Abstract
During the combined fatigue test of certain engine fan blade,the difficulty was how to combine low cycle fatigue and high cycle fatigue,and applied them to the assessment location of the blade. The modal analysis and test was carried to obtain the natural frequency of the blade and verify the accuracy of the model. By the static analysis and transient analysis of blade-wheel system,the critical part and the frequency of high cycle fatigue was acquired. Besides,the holder was designed and combined the blade into a system. Through the demonstration of simulation analysis and fracture analysis,high-low cycle combined loading was successfully applied to the assessment location of the blade. The results show that for the third-level fan blade,the regularity distributions of equivalent stress have a similarity under different revolving speed loads. The dangerous part of the blade is on the lug,and the max stress reached to 503 MPa. There are 2 risky resonance revolving speeds in the bladewheel system,which are n = 9 890. 92 r/min and n = 10 979. 8 r/min. The resonance frequencies are f = 1 318. 92 Hz and f =1 439. 65 Hz. There are typical characteristics of high-low cycle compound fatigue fracture on the cracked areas of the blade,such as fatigue line and fatigue striation.
