Noise–Vibration Monitoring and Analysis of Aero-Engine Blade Fracture Faults

Abstract

This study investigates the vibration and noise response characteristics of faulty blades through mechanistic modeling and validates the established model via full-scale engine tests. In the modeling stage, based on the physical mechanism of wake-induced aerodynamic excitation acting on blades, the dynamic characteristics of the aerodynamic force acting on the first-stage high-pressure blade are analyzed. A stator blade model is developed, incorporating aerodynamic dynamic pressure theory, a Rayleigh damping formulation, and a fourth-order finite-difference approximation to describe the blade bending stiffness. The governing equations are discretized using the finite difference method, and the blade response under aerodynamic excitation is solved using the Newmark-β method; this process establishes the coupling relationship between aerodynamic excitation and system dynamic response. The numerical results indicate that blade fracture leads to a pronounced amplification of the rotor shaft rotational frequency component, while the amplitudes of the blade passing frequency (BPF) and its harmonics are significantly attenuated. Further, full-scale engine tests were designed and carried out under three operating conditions for both healthy and fractured blades. Signal processing results demonstrate that the extracted fault features are in good agreement with the predicted system dynamic response, thereby the experimental results confirm the accuracy and validity of the proposed model. The conclusions of this study provide a reliable theoretical reference and quantitative benchmark for identifying the response characteristics of blade fracture faults in aero-engines, providing practical engineering value for the fault diagnosis and health monitoring of blades.

Conflict of Interest Statement

The authors declare no conflicts of interest.