To deal with foreign object damage (FOD) notch-type damages which the leading edge of TC4 titanium alloy fan/compressor blades suffered

test study on high-speed ballistic impacts

and analysis of damage characteristics and stress concentrations were carried out under different impact angles

while high cycle fatigue tests and fatigue limit strength prediction of as-impacted and residual stress relief annealed specimens were conducted. Conclusions were made below: with the increase of impact angles

damage sizes at incident side and stress concentrating coefficients remained constant

and the notched damage depth and length decreased. The range of the damage depth was 0.6－1.5mm

and the range of stress concentrating coefficients was 2.6－3.4. The fatigue limit strength of notch-type damaged specimens reduced to 27%－35% of smooth specimens

and was not inverse to stress concentrating coefficients. The high cycle fatigue (HCF） behavior of annealed specimens declined slightly or remained basically unchanged

indicating that the effect of the residual stress was slight. Influence of the residual stress on the fatigue limit strength was less than 10% of the smooth specimen. The HCF behavior of notch-type damaged specimens had no obvious correlation with the damage root radius

but declined with the increase of the maximum damage depth and damage length

indicating that special consideration must be given when preparing the maintenance manual. Prediction accuracy of HCF behavior by Peterson formula was unsatisfactory

of which the maximum error was 45%. It required to develop high precision prediction method for HCF behavior of FOD notch-type damaged components.