• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.364-370
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• 2019

In this paper, an individual blade control (IBC) methodology is applied to find the best input scenario for vibratory hub loads reduction of XH-59A co-axial rotorcraft in high speed flight. A comprehensive aeromechanics analysis code CAMRAD II is employed to analyze the aircraft. A parametric study is conducted for optimum IBC inputs leading to the maximum vibration reduction. Numerical results demonstrate that up to 50% reduction in the hub vibration index is obtained for an IBC input at 3/rev frequency with the amplitude and phase angle of 0.5 deg. and 300 deg., respectively. The upper rotor exhibits as much as 6% more vibration reduction as compared to that of the lower rotor due to a clean inflow characteristic of the rotor. It is found that further vibration reduction gain is reached for IBC inputs with advancing-side only control. The hub vibration becomes reduced by up to 17% in reference to that with full rotor disk control. It is noted that the additional gain is obtained with significantly less power input with the advancing-side only control.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.499-505
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• 2012

Vibratory loads imposed by the rotating blade upon the fuselage has been one of major obstacles in rotorcrafts. A new concept of rotor blade is currently developed to adopt an Active Trailing-edge Flap (ATF) to alleviate such obstacles. The flap is mounted at 65~85% spanwise location from the rotor hub. The nominal rotational speed of the blade is as high as 1,528 RPM, to match the required tip Mach number. Structural integrity is one of the important design aspects to be maintained and monitored in this special type of rotor. This is due to that many detailed components, which drive the flap, are inserted inside the rotating blade. To conduct its structural design and analysis, CAMRAD-II and the one-dimensional beam analysis are used. At the same time, three-dimensional finite element analysis are also used, such as MSC. PATRAN/NASTRAN, in order to analyze the details of the present active blade. As a result, comparable characteristics for the present rotor are predicted by both approaches.