Foreign object damage on the leading edge of gas turbine blades

Abstract

The severe damages to the leading edge of aircraft blades occur when millimeter-sized particles such as sands, gravels or even the pieces of the engine components impact those of blades, which is called hard body impact or foreign object damage. This damage produces the geometry discontinuity such as the notch on the blades which becomes the site for fatigue crack initiation.FOD on the leading edge of the turbine blade is done by using the finite element method in this paper. Experimental stress analysis is performed for investigating the stress concentration factor at the crater base and is compared with the data from the finite element and the analytical method. The comparison shows that the finite element method results agree well with the experimental and analytical data at the crater base. Then the residual stress along the largest blade length is obtained for the potential crack initiating regions, and at the end, the analysis focuses on the comparison between the quasi-static indentation and fully dynamic impact for three critical locations where the tensile residual stresses cause crack initiation.