Vibration fault diagnosis for aero-engine based on trend model

By summarizing characteristics of body vibration faults for ten aero-engines, frequency analysis indicates that most of fault mechanisms are related with rotor fundamental frequency. However, different fault mechanism has different vibration trend. Thus, using trend model can effectively identify a certain fault mechanism. Firstly this paper discussed the mathematical description of engine vibration trend and the characteristics of each trend development. Secondly steady vibration model, shimmy model, linear vibration model and step change vibration model were set to describe the normal and three typical fault situations. In order to efficaciously distinguish the four trend models mentioned above, recognition criteria was set up and recognition algorithm was realized. Finally, four actual groups data for engines were used to verify the correctness and engineering practicability of this method. The results demonstrate that vibration fault diagnosis for aero-engine based on trend model can distinguish the fault mode.