Analytical and experimental evaluation of active structural acoustic control (ASAC) of helicopter cabin noise

Mathur, Gopal P.; Oconnell, J. M.; Janakiram, Ram D.; Fuller, Chris R.

doi:10.2514/6.2002-1035

Cited by 4 publications

(4 citation statements)

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“…where 0 is the amplitude of the force. According to (9), the relationship of the displacement and force at the two ends of the strut can be obtained:…”

Section: Transfer Characteristicsmentioning

confidence: 99%

“…The boundary conditions for the strut freed at the upper side and the base excited at its lower side by a harmonic longitudinal displacement can be expressed as follows: where 0 is the amplitude of the displacement. According to (9), the relationship of the displacement and force at the two strut ends can be obtained:…”

Section: Transfer Characteristicsmentioning

confidence: 99%

“…The smart strut consists of piezoelectric actuators that are directly bonded to the BK117 support struts and provides good effectiveness at controlling the noise of multiple gear mesh frequencies in a flight test. In addition, the Sikorsky Aircraft Corporation and the Boeing Company each utilized different point force actuators mounted near the support struts [3,9]. The active noise control (ANC) system uses cabin noise as feedback and produces a high capability to reduce the primary gear mesh tone over a wide range of steady and transient flight conditions.…”

Section: Introductionmentioning

confidence: 99%

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Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Yang

Wang

2017

Shock and Vibration

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A special periodic strut is developed to reduce the helicopter cabin noise in this paper. The strut exhibits unique dynamic characteristics which can isolate the gearbox vibrations from transferring to the fuselage and radiating noise. Modeling, simulation, and experimental research are carried out to explore its characteristics and performance. A theoretical model of the strut is firstly established, with particular emphasis on correlating the passband and stop band behaviors with the damping and a series of boundary conditions. Then, through simulations, it is shown that both the damping and boundary conditions have significant influences on the stop band, including the beginning and end frequencies and attenuation effects. Based on these analytical simulations, experimental analyses are conducted with the newly developed strut. Inspiring performances are validated under different conditions. Considering that the helicopter vibration in practical applications is much more complex, further experimental investigations are carried out on a helicopter model, which generates prominent gear mesh tones similar to a real helicopter. The experimental results show that the compounded periodic strut can significantly attenuate the vibrations transmitted to the fuselage. Compared with the plain strut, attenuations in excess of 40 dB are measured in the frequency range from 300 to 2000 Hz.

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“…where 0 is the amplitude of the force. According to (9), the relationship of the displacement and force at the two ends of the strut can be obtained:…”

Section: Transfer Characteristicsmentioning

confidence: 99%

Section: Transfer Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Yang

Wang

2017

Shock and Vibration

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“…Recently, considerable advances have b,een achieved by using smart structure technologies. For example, piezoelectric actuators have been attached to helicopter airframe panels to reduce sound radiation [8,9]. This, approach is generally effective for resonant frequencies.…”

Section: Cabin Noise Reductionmentioning

confidence: 99%

Development of Smart Structure Systems for Helicopter Vibration and Noise Control

Chen

Wickramasinghe

Zimcik

2007

Transactions of the Canadian Society for Mechanical Engineering

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Helicopters are susceptible to high vibratory loads, excessive noise levels and poor flight stability compared to fixed-wing aircraft. The multidisciplinary nature of helicopter structures offers many opportunities for the innovative smart structure technology to improve helicopter performance. This paper provides a review of smart structures research at the National Research Council Canada for helicopter vibration and cabin noise control applications. The patented Smart Spring approach is developed to vary the blade impedance properties adaptively to reduce the vibratory hub loads transmitted to the fuselage by vibration reduction at the source. A smart gearbox strut and active structural acoustic control technologies are investigated to suppress the vibration and tonal gear meshing noise into the cabin either by modifying the vibration load transmission path, or weakening the coupling between exterior and cabin acoustic fields. Two adaptive seat mount concepts are proposed to reduce the vibration of the aircrew directly to improve ride quality of the vehicle.

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Active structural acoustic control of helicopter interior multifrequency noise using input-output-based hybrid control

Yang

Wang

2017

Journal of Sound and Vibration

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Analytical and experimental evaluation of active structural acoustic control (ASAC) of helicopter cabin noise

Cited by 4 publications

References 0 publications

Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Research on the Vibration Characteristics of a Compounded Periodic Strut Used for Helicopter Cabin Noise Reduction

Development of Smart Structure Systems for Helicopter Vibration and Noise Control

Active structural acoustic control of helicopter interior multifrequency noise using input-output-based hybrid control

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