Vibration fatigue testing method for large-bypass-ratio engine fan blade with shoulder

Abstract

The invention belongs to the technology of aviation engine blade testing, and provides a vibration fatigue testing method for a large-bypass-ratio engine fan blade with a shoulder. The method comprises the steps: (1) laterally cutting the fan blade with the shoulder; (2) machining the top of the shoulder into two parallel platforms; (3) enabling a clamp pedestal to be fixedly connected with a vibrating platform; (4) binding strain gages on the blade body; (5) enabling a testing blade with the strain gages to be placed on an inner clamping surface of a dedicated clamping block; (6) enabling the dedicated clamping block with the testing blade to be placed into a frame of the clamp pedestal for compression; (7) enabling the lead of each strain gage on the testing piece to be connected with a corresponding channel of a deformeter; (8) controlling the vibration sweep frequency of a small load of the vibration platform, and finding a first-order bending resonance frequency of the blade; (9) recording the strain value of each channel and the amplitude of a blade tip through the deformeter, determining the maximum stress position, and carrying out the fitting of the relation between the maximum stress and the amplitude of the blade tip; (10) solving a required testing load value, and completing the vibration fatigue testing.

Description

technical field [0001] The invention belongs to the test technology of aeroengine blades, and relates to a test method for evaluating the vibration strength reserve and service life of a fan blade with a shoulder of a large bypass ratio engine. Background technique [0002] The vibration fatigue strength assessment test of the engine blade is an indispensable and important link in the development and production of the engine. The results of the assessment test are very important for the engine's working safety, fault analysis and troubleshooting. The results of the vibration fatigue strength assessment test are an important test basis for whether the blade is allowed to be installed. [0003] Usually, in the blade vibration fatigue test, in order to assess the large stress area of ​​the blade body (usually near the tenon of the blade body), the blade body is fixed at one end at the tenon, and the blade body is suspended in the air. Vibration stress can be effectively applie...

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Problems solved by technology

[0004] For fan blades with protruding shoulders for high bypass ratio engines, the document requires the assessment of the fatigue strength of two large stress areas near the protruding shoulders and near the tenons of the blade body. According to the above method, only the assessment of the vicinity of the tenons of the blade body can be completed, but not Check around shoulder

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