Abstract: An example system for disconnecting a driven member from a driving member is described. The system includes a vibration detection device configured to output vibration signals indicative of vibration levels of the driven member. The system also includes a controller including at least one processor. The controller is arranged to (i) determine that a vibration signal output by the vibration detection device satisfies a threshold condition and (ii) based at least on the determination that the vibration signal satisfies the threshold condition, trigger a mechanical disconnection of the driven member from the driving member by a mechanical disconnect device.

Abstract: Systems and methods are provided for an aircraft propulsor configured to generate electrical power through a variable frequency generator in response to rotation of a gear train. The aircraft propulsor includes compensation circuitry. The aircraft propulsor further includes exciter circuitry that, when powered by an excitation signal, generates a magnetic field that interacts with a rotating variable frequency generator to generate electrical power. The exciter circuitry may be powered by at least a portion of the power generated by the variable frequency generator. The compensation circuitry may adjust the excitation signal to reduce the effect of torsional oscillation of the gear train and/or the variable frequency generator on the quality of power produced by the variable frequency generator.

Abstract: An example system for disconnecting a driven member from a driving member is described. The system includes a vibration detection device configured to output vibration signals indicative of vibration levels of the driven member. The system also includes a controller including at least one processor. The controller is arranged to (i) determine that a vibration signal output by the vibration detection device satisfies a threshold condition and (ii) based at least on the determination that the vibration signal satisfies the threshold condition, trigger a mechanical disconnection of the driven member from the driving member by a mechanical disconnect device.

Abstract: Systems and methods are provided for an aircraft propulsor configured to generate electrical power through a variable frequency generator in response to rotation of a gear train. The aircraft propulsor includes compensation circuitry. The aircraft propulsor further includes exciter circuitry that, when powered by an excitation signal, generates a magnetic field that interacts with a rotating variable frequency generator to generate electrical power. The exciter circuitry may be powered by at least a portion of the power generated by the variable frequency generator. The compensation circuitry may adjust the excitation signal to reduce the effect of torsional oscillation of the gear train and/or the variable frequency generator on the quality of power produced by the variable frequency generator.

Abstract: An engine assembly, an acoustical liner and an associated fabrication method are provided to address fan blade flutter and fan noise control simultaneously within the same liner area. Fan blade flutter is therefore controlled without necessarily increasing the weight of the engine, impairing the structural integrity of the engine, or increasing the noise generated by the engine. The acoustical liner may have additional acoustical degrees of freedom which permit these seemingly competing concerns to be addressed in a complementary manner. The acoustical liner may include inner and outer barrels with the inner barrel having a perforated face sheet, a perforated back skin and a core disposed between the perforated face sheet and the back skin. The fluid communication between the core and the space between the inner and outer barrels provides additional acoustical degrees of freedom which may be utilized to reduce fan blade flutter while concurrently limiting fan blade noise.

Abstract: An engine assembly, an acoustical liner and an associated fabrication method are provided to address fan blade flutter and fan noise control simultaneously within the same liner area. Fan blade flutter is therefore controlled without necessarily increasing the weight of the engine, impairing the structural integrity of the engine, or increasing the noise generated by the engine. The acoustical liner may have additional acoustical degrees of freedom which permit these seemingly competing concerns to be addressed in a complementary manner. The acoustical liner may include inner and outer barrels with the inner barrel having a perforated face sheet, a perforated back skin and a core disposed between the perforated face sheet and the back skin. The fluid communication between the core and the space between the inner and outer barrels provides additional acoustical degrees of freedom which may be utilized to reduce fan blade flutter while concurrently limiting fan blade noise.

Abstract: Buried fluid containing conduits, such as natural gas lines, are located by providing variable frequency sinusoidal excitation acoustic signals over a broad frequency range to the fluid content of the conduit so that the conduit will vibrate and cause elastic vibration in the media in which such conduit is buried. A plurality of measurements of said vibrations are taken on the surface of the media or ground in which such conduit is buried. The measurements are taken laterally of the estimated position of the conduit. The position of the conduit is determined by changes in the characteristics of the vibrations caused by the differences in distances between the pipe and the measurements.

Abstract: An accelerometer is attached to a pipe wall to measure the acoustic pressure waves generated in a fluid within the pipe as a result of a leak in a valve in the pipeline. Calibrating the accelerometer and tuning it to particular wave frequencies allows a determination of the magnitude of the leak through the valve.