Dynamically Coupled Systems

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A major focus of the applicant's research program in the recent years has been the development of a realistic structural and dynamic model of a smart helicopter rotor blade that can be used to simulate dynamic behaviour of these blades with a high degree of fidelity. A continuous model of a smart rotor blade, without initial span-wise twist, was developed in the previous phase of this research program. This model that incorporates integrated piezoelectric fibres as Macro Fibre Composites (MFC) can be used to investigate the controllability of undesirable dynamic responses by using the piezoelectric actuators to influence the dynamic response of the blades. Building on the developments of the previous phase of this research program, the next phase will include the following objectives:****1. Investigate the capability and versatility of smart Macro-Fibre Composite (MFC) helicopter rotor blades to control Blade Sailing Phenomenon (BSP) in shipboard helicopters has been under investigation in my research group. During start-up and shut-down operations of helicopter rotor blades on ship decks, the elastic response of blades is of concern for flight safety and personnel reasons. While the rotors are being engaged or disengaged on a shipboard helicopter, at low speeds of rotation they can be subjected to high wind-induced aerodynamic forces without the benefit of the centrifugal stiffening present at the higher normal operating speeds. This excitation combined with ship deck motion and wind conditions has the potential of resulting in excessive deformations in rotor blades that is referred to as the BSP. As the result, the rotor blades can come into contact with the fuselage or tailboom of the helicopter. This phenomenon, while resulting in substantial levels of airframe damage with the possibility of bringing the airworthiness of the vehicle into question, also compromises the safety of flight crew and the ship deck personnel quite seriously. To reduce the BSP, this research program will develop an active control strategy using active twist through embedded MFCs to augment passive control strategies, like increasing the collective pitch setting.****2) This program will also include optimization of the placement and configuration of the integrated MFC actuators in the blade to obtain the best actuation authority.****3) The existing development does not take into account the effect of initial twist that is present in most, if not all, modern helicopter rotor blades. A more realistic modelling of rotor blades requires the incorporation of such a feature in cross-sectional analysis.****4) The rotor blade model that is developed for rotorcrafts in the previous phase of this research program can now be further developed and applied to investigate the dynamic behaviour of horizontal axis wind turbine (HAWT) and to predict the power and torque developed in HAWT farms both off-shore and land-based.******