Paper Title
Fatigue Life Estimation of Critical Components of Helicopter Using Flight Data Recorder (FDR)

Helicopter is a heavier than air machine capable of flying vertically and hover in the air, made of a lot of rotating and non-rotating components which are subjected to highly alternate loading. The source of these loads is harmonic variation of aerodynamic loading of the rotating wing. The critical loading of these components is not static load, to be compared to yield strength, but it is rather fatigue load. Fatigue Life of these critical components has been obtained during the initial design and development stages based on the mission spectrum provided by the users. Any change in mission spectrum usage can have effect on the life of the critical components. So there is a need to re-estimate the fatigue life of these components on a regular basis. User spectrum of Helicopter to be found using the FLIGHT DATA RECORDER (FDR) data. An algorithm to be written to find the spectrum from the FDR data. Based on the spectrum obtained, a fitting load spectrum has to be obtained from the database of prototype helicopter sorties. This paper presents obtained load spectrum of components using Rain flow methodologies. Finally fatigue life to be calculated using Miner’s damage calculation method. Keywords— Helicopter, Loading, Fatigue, Spectrum, Damage.