A Method and System for Identifying Timing Vibration Parameters of Rotating Blade Tips

Abstract

The invention discloses a tip timing vibration parameter identification method for a rotating blade. The method comprises the following steps of determining the number of tip timing sensors and circumferential installation positions; collecting an under-sampled signal of a vibration displacement of the rotating blade; building a sparse representation model of the under-sampled signal, and determining a vibration frequency of the blade by using a sparse reconstruction method; and obtaining a vibration order of the blade based on the vibration frequency of the blade determined by the sparse reconstruction method and a rotation frequency of the blade, building a blade vibration equation design matrix based on the vibration order of the blade and the installation positions of the tip timing sensors, and identifying a vibration amplitude of the rotating blade by using a circumferential Fourier method. The invention further provides a tip timing vibration parameter identification system forthe rotating blade. According to the method and the system, no additional prior information is needed; the vibration frequency and amplitude parameters of the blade can be identified by measuring theunder-sampled signal of the vibration displacement only by utilizing the tip timing sensors; the vibration parameter identification step is simplified; and the precision of an identification result ishigh.

Description

technical field [0001] The disclosure belongs to the technical field of non-contact vibration testing of rotating machine blades, and in particular relates to a method and system for identifying timing vibration parameters of a rotating blade tip. Background technique [0002] Rotating blades are important components in aero-engines. The harsh environment of high temperature, high pressure, and high speed in which the aero-engine works can easily cause blade vibration, and blade vibration often causes high-cycle fatigue cracks or other damage to the blade. Conversely, damage to the aero-engine blade will change the vibration of the blade. state. Therefore, effective identification of vibration parameters such as vibration frequency and amplitude of high-speed rotating blades can realize the monitoring of the vibration state of the blades so as to detect blade failures in time and avoid more serious accidents. [0003] As a non-contact measurement technology, blade tip timi...

AI Technical Summary

Problems solved by technology

The existing blade tip timing post-processing method has low accuracy in the identification of the blade vibration amplitude, and the amplitude parameter of the blade vibration has a great influence on the inversion accuracy of the subsequent dynamic strain at the key position of the blade, and the blade strain Condition plays an important role in assessing the remaining life of the blade

The circumferential Fourier method is an effective means to identify the vibration amplitude of the blade, but the construction of its design matrix needs to provide prior information through finite element analysis. The complex working conditions of the aeroengine will cause the blade vibration state to change, making the prior information Inconsistent with the actual situation, which leads to the identification error of the vibration amplitude parameter

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