Advanced Approaches to Helicopter Engine System Dynamics

The advancement in the modelling and analysis of the helicopter/engine as a system can help to better understanding the vibrations and loads in the overall structure. The linear and rotor induced non-linear dynamic response of the helicopter coupling with its gas turbine engines under the main gear box vibration, engine rotor unbalance, inadvertent release of rotating mass and foreign object ingestion must be considered in the design of the structures. Custom-developed and commercially available tools combined together as a total system prediction process can more accurately evaluate overall structural vibrations and dynamic responses. The analysis also takes into consideration the material non-linearity, large deformation and damping. The fidelity of the prediction system is greatly enhanced by calibration with helicopter and engine test data. As a result, the prediction of structural loads and vibrations at the mount interfaces, engine casings and helicopter structures are made available up-front in the design cycle to help critical structural evaluations. The advancement of a system prediction method is also the prerequisite to address overall helicopter/engine safety and reliability, and to reduce noise.