This paper deals with the sources of helicopter vibration and noise emissions. It shows and evaluates adaptive concepts to reduce them. The main reasons for these emissions are aerodynamic effects such as blade‐vortex‐inter action (BVI), aerodynamic hysteresis, and local transonic effects at the forward moving blade.
After a review of conventional control concepts to reduce the vibrations and/or sound emissions, the possibilities to realise an adaptive rotorblade are explained.
The understanding of the interaction between the aerodynamic sources and the resulting vibrations and noise is the basis of the design of optimal control concepts.
Based on experiments with flat specimens made of injection moulded short glass fibre reinforced polyamide 6.6 with 50 % fibre content the damage accumulation under variable amplitude loading was investigated with the consideration of notches (Kt =1.0, Kt =2.5 and Kt =9.8), mean stresses (R =-1 and R=0) and temperatures (T =RT and 130°C). Furthermore, fatigue tests with components made of the same material were performed. Concluding, the transferability of the determined results obtained with specimens to components was investigated by applying local concepts. These results provide the basis for the structural durability design for components made of short fibre reinforced polymers and serve as input for the calculation methodology
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