Aeronautics and astronautics – Miscellaneous
Patent
1994-12-05
1996-09-24
Kashnikow, Andres
Aeronautics and astronautics
Miscellaneous
244 1R, 244134R, 244134D, 244 53R, 415118, 415119, 310322, 310324, B64D 2900, F02C 7045
Patent
active
055582982
ABSTRACT:
An active noise control subassembly for an aircraft engine. An aircraft engine noise radiating panel is bendably vibratable to generate a canceling noise generally opposite in phase to at least a portion of the discrete tonal noise produced by the engine. A piezoceramic actuator plate is vibratable by an applied electric AC signal. The plate is connected to the panel such that vibrations in the plate cause bending vibrations in the panel and such that the plate is compressively prestressed along the panel when the panel is free of bending vibrations. The compressive prestressing increases the amplitude of the canceling noise before the critical tensile stress level of the plate is reached. Preferably, a positive electric DC bias is also applied to the plate in its poling direction to increase the amplitude of the canceling noise before the sum of the AC signal and DC bias exceeds the depolarization voltage in a direction opposite to the poling direction.
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Concurrently filed U.S. patent application RD-23996, Frederick G. Pla and Harindra Rajiyah, entitled "Active Vibration Control of Structures Undergoing Bending Vibrations".
U.S. patent application Ser. No. 08/051,810, filed Apr. 21, 1993, Frederick G. Pla, entitled "Active Control of Aircraft Engine Noise Using Vibrational Inputs".
U.S. patent application Ser. No. 08/143,602, filed Nov. 1, 1993, Frederick G. Pla et al., entitled "Active Noise Control Using Noise Source Having Adaptive Resonant Frequency Tuning Through Stiffness Variation".
U.S. patent application Ser. No. 08/143,605, Filed Nov. 1, 1993, Pla et al., entitled "Active Noise Control Using Noise Source Having Adaptive Resonant Frequency Tuning Through Stress Variation".
U.S. patent application Ser. No. 08/143,604, Filed Nov. 1, 1993, Pla et al., entitled "Active Noise Control Using Noise Source Having Adaptive Resonant Frequency Tuning Through Variable Panel Loading".
U.S. patent application Ser. No. 08/143,603, Filed Nov. 1, 1993, Pla et al., entitled "Active Noise Control Using Noise Source Having Adaptive Resonant Frequency Tuning Through Variable Ring Loading".
Pla Frederic G.
Rajiyah Harindra
Dinh Tien
Erickson Douglas E.
General Electric Company
Kashnikow Andres
Snyder Marvin
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