The invention provides a
foreign object damage gap calibration method capable of ensuring that a
stress concentration coefficient is not less than 3. The method comprises the following steps of firstly, prefabricating an FOD notch in a blade, carrying out three-dimensional reconstruction on FOD damage through a three-dimensional
optical scanning system to establish an FOD damage model; performingfinite
element analysis on the blade model with an FOD, which is reversely obtained by three-dimensional reconstruction, calculating to obtain a
stress concentration coefficient of the blade model, and recording a
stress concentration coefficient value corresponding to the typical damage size; and building a neural
network model by using a
programming language, taking the damage size as the inputof the neural network, taking the stress concentration coefficient as the output of the neural network, and training the neural
network model through loop iteration; and calibrating the damage size corresponding to the type of blade Kt = 3 through the trained network. When the anti-FOD capacity of the blade is assessed, an FOD notch can be prefabricated in the
front edge of the blade through an air cannon method or a notch
machining method according to the calibrated damage size.