Foreign object damage on the leading edge of a thin blade

Foreign object damage (FOD) occurs when hard, millimeter-sized objects such as gravel or sand are ingested into aircraft jet engines. Particles impacting turbine blades at velocities up to about 300 m/s produce small indentation craters which can become sites for fatigue crack initiation, severely limiting the lifetime of the blade. In this study, the impact on the edge of a thin plate is investigated by using the finite element method. Dimensional analysis is used to group the impact and material variables into the smallest possible sets characterizing FOD. Primary focuses are addressed on the effects of residual stress and stress concentration, and the implication of fatigue cracking at different locations is given. These results provide useful insights for the real FOD and fatigue cracking problems encountered in turbine engines.