The concept of active blade twisting as a method for reducing helicopter noise and vibration during flight is presented. Active twisting is achieved through piezoelectric actuators embedded in the blade skin, which generate dynamic twist when subjected to an electric field. Such dynamic deformation can lower fuel consumption while also reducing noise and vibration levels. A methodology for determining the optimal geometric dimensions of the cross-section of a helicopter blade, taking into account design constraints, is proposed to achieve the maximum twist angle of the blade under the action of piezoelectric actuators. First, a three-dimensional numerical model of the BO 105 model-scale rotor blade is developed in the finite element software ANSYS 16.0. The effect of the rotor blade’s cross-sectional dimensions on the cross-sectional properties and twist angle is investigated. It is found that skin thickness, spar flange thickness, and spar flange length affect the twist angle, with skin thickness showing a significant effect. Based on these results, an optimisation strategy is formulated to identify the optimal blade cross-section configuration to achieve the maximum twist angle. It was established that with the optimised geometric parameters of the cross-section the maximum active twist reaches 5.2°, while the positions of the elastic axis and the centre of gravity exhibit only minor deviations from those of the reference model. The placement of the piezoelectric actuators has a significant influence on both the flapwise bending stiffness and the torsional stiffness of the blade.
Andrejs Kovaļovs (Wed,) studied this question.