A method for evaluating the FOD resistance of an aero-engine blade

Abstract

The invention relates to a method for evaluating the FOD resistance of an aero-engine blade. The method comprises steps of carrying out impact dynamics simulation of foreign object damage on a simulated blade numerical model; obtaining the relation between the macroscopic characteristics of the notch and the foreign object type, the impact speed and the impact angle, determining foreign object damage test conditions on the basis of the relation, carrying out an external simulated object damage test on the simulated blade by using an air cannon, and observing the macroscopic characteristics ofthe impact notch; Taking the static stress and the dynamic stress under the working load at the dangerous position of the front edge of the blade as the initial static load and the dynamic load of thehigh-cycle fatigue test, carrying out the high-cycle fatigue test on the damaged simulated blade, obtaining the high-cycle fatigue strength of the blade through a stepping method, and evaluating theFOD resistance of the blade according to the result of the high-cycle fatigue test; And carrying out foreign object damage simulation and high-cycle fatigue test on a small number of real blades to obtain the high-cycle fatigue strength of the real blades so as to verify the conformity of the simulated blades and the real blade test result.

Description

technical field [0001] The invention relates to the field of performance testing of aeroengine blades. Background technique [0002] During take-off and landing on the runway or aircraft carrier deck, the aero-engine running at high speed will often inhale hard objects such as stones, gravel, bolts, metal fragments, etc. When these foreign objects enter the engine, the relative speed of the compressor blades can reach 100m / s-350m / s, it will cause serious impact damage to the blades of the first few stages of compressors, especially the leading edge of the blades. In the prior art, the damage caused by hard objects such as metal and sand hitting the engine is called "foreign object damage" (abbreviated as FOD, Foreign Object Damage) [0003] If the damaged blades are not detected and treated in time, fatigue fracture failure may occur under high-frequency vibration, and the flying blades will break through the casing and even damage the blades of the subsequent compressor s...

AI Technical Summary

Problems solved by technology

However, the root cause of the fracture of the blade after being subjected to FOD is that there will be microscopic cracks, stress concentration, residual stress and microstructure damage in the damaged part formed by the impact, and the damaged part will easily become a source of fatigue under high-cycle working load and cause fatigue fracture

Moreover, the high-cycle fatigue failure of metals has a large dispersion, and the ability of the blade to resist foreign object damage can only be assessed by the number of cycles that can work after damage, which cannot effectively avoid the risk of blade failure caused by foreign object damage

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