Abstract: An aircraft control structure for drag management includes a nozzle structure configured to exhaust a swirling fluid stream. A plurality of swirl vanes are positioned within the nozzle structure, and an actuation subsystem is configured to cause the plurality of swirl vanes to move from a deployed state to a non-deployed state. In the non-deployed state, the plurality of swirl vanes are substantially flush with the inner surface of the nozzle structure. In the deployed state, the plurality of swirl vanes produce the swirling fluid stream.

Abstract: A method of imaging a test subject includes providing one or more moveable sensors to sense an attribute of the test subject (e.g., acoustic pressure), wherein the attribute has a tonal noise component and a broadband noise component. A rotational sensor is provided to sense a rotational velocity of a rotational element of the test subject. Each of the moveable sensors are moved along a path while continuously acquiring test data that is indicative of the rotational velocity of the rotational element, the sensed attribute, the position, and the orientation of each of the moveable sensors. A set of transfer functions corresponding to points in space that have been visited by the moveable sensors are constructed, each of the transfer functions relating the test data of the moveable sensors to the test data of the rotational sensor. A visual representation of the tonal noise component of the attribute in a region adjacent the test subject is produced using the set of transfer functions.

Abstract: An aircraft control structure can be utilized for purposes of drag management, noise control, or aircraft flight maneuvering. The control structure includes a high pressure engine nozzle, such as a bypass nozzle or a core nozzle of a turbofan engine. The nozzle exhausts a high pressure fluid stream, which can be swirled using a deployable swirl vane architecture. The control structure also includes a variable geometry pylon configured to be coupled between the nozzle and the aircraft. The variable geometry pylon has a moveable pylon section that can be deployed into a deflected state to maintain or alter a swirling fluid stream (when the swirl vane architecture is deployed) for drag management purposes, or to assist in the performance of aircraft flight maneuvers.

Abstract: A continuous scanning method employs one or more moveable sensors and one or more reference sensors deployed in the environment around a test subject. Each sensor is configured to sense an attribute of the test subject (e.g., sound energy, infrared energy, etc.) while continuously moving along a path and recording the sensed attribute, the position, and the orientation of each of the moveable sensors and each of the reference sensors. The system then constructs a set of transfer functions corresponding to points in space between the moveable sensors, wherein each of the transfer functions relates the test data of the moveable sensors to the test data of the reference sensors. In this way, a graphical representation of the attribute in the vicinity of test subject can be produced.

Abstract: A modular crossing system generally includes a set of modules and a set of segments (e.g., bridge segments). Each segment includes a subset of the set of modules, and at least a portion of the set of segments are configured to be rotateably interlocked with a subsequent segment such that the set of segments form a crossing assembly having a deployed state and a collapsed state. Each module of the set of modules may include a hinge pin opening configured to removeably accept one of the set of hinge pins. The set of segments may be rotateably interlocked via the set of hinge pins.

Abstract: An aircraft control structure for drag management includes a nozzle structure configured to exhaust a swirling fluid stream. A plurality of swirl vanes are positioned within the nozzle structure, and an actuation subsystem is configured to cause the plurality of swirl vanes to move from a deployed state to a non-deployed state. In the non-deployed state, the plurality of swirl vanes are substantially flush with the inner surface of the nozzle structure. In the deployed state, the plurality of swirl vanes produce the swirling fluid stream.

Abstract: A multi-sine vibration testing method includes coupling a vibratory excitation source and a sensor to a test structure, then providing a reference signal to the excitation source, wherein the reference signal comprises a first sinusoidal waveform having a first frequency and a second sinusoidal waveform having a second frequency different from the first frequency. The first frequency and the second frequency each sweep between a corresponding start value and a corresponding end value, and the frequency response is measured from each of the sensors while providing the reference signal.

Abstract: An aircraft control structure can be utilized for purposes of drag management, noise control, or aircraft flight maneuvering. The control structure includes a high pressure engine nozzle, such as a bypass nozzle or a core nozzle of a turbofan engine. The nozzle exhausts a high pressure fluid stream, which can be swirled using a deployable swirl vane architecture. The control structure also includes a variable geometry pylon configured to be coupled between the nozzle and the aircraft. The variable geometry pylon has a moveable pylon section that can be deployed into a deflected state to maintain or alter a swirling fluid stream (when the swirl vane architecture is deployed) for drag management purposes, or to assist in the performance of aircraft flight maneuvers.

Abstract: A fairing includes three sections: an aft section, a middle section, and a nose section. The aft section includes a first surface having a generally constant conic angle (i.e., a “boat-tail angle”) with respect to the longitudinal axis such that the aft section tapers to a first end configured to attach to a generally cylindrical body. The middle section, which intersects and is axially aligned with the aft section, has a second surface characterized by a constant elliptical cross-section along a plane orthogonal to the longitudinal axis. The nose section intersects and is axially aligned with the middle section. The nose section is further defined by four generally concave trianguloid surfaces, each extending from the middle section to a common apex intersecting the longitudinal axis, wherein each adjacent pair of trianguloid surfaces intersects at an edge (e.g., an incurvate edge).

Abstract: A continuous scanning method employs one or more moveable sensors and one or more reference sensors deployed in the environment around a test subject. Each sensor is configured to sense an attribute of the test subject (e.g., sound energy, infrared energy, etc.) while continuously moving along a path and recording the sensed attribute, the position, and the orientation of each of the moveable sensors and each of the reference sensors. The system then constructs a set of transfer functions corresponding to points in space between the moveable sensors, wherein each of the transfer functions relates the test data of the moveable sensors to the test data of the reference sensors. In this way, a graphical representation of the attribute in the vicinity of test subject can be produced.

Abstract: A multi-sine vibration testing method includes coupling a vibratory excitation source and a sensor to a test structure, then providing a reference signal to the excitation source, wherein the reference signal comprises a first sinusoidal waveform having a first frequency and a second sinusoidal waveform having a second frequency different from the first frequency. The first frequency and the second frequency each sweep between a corresponding start value and a corresponding end value, and the frequency response is measured from each of the sensors while providing the reference signal.

Abstract: A fairing includes three sections: an aft section, a middle section, and a nose section. The aft section includes a first surface having a generally constant conic angle (i.e., a “boat-tail angle”) with respect to the longitudinal axis such that the aft section tapers to a first end configured to attach to a generally cylindrical body. The middle section, which intersects and is axially aligned with the aft section, has a second surface characterized by a constant elliptical cross-section along a plane orthogonal to the longitudinal axis. The nose section intersects and is axially aligned with the middle section. The nose section is further defined by four generally concave trianguloid surfaces, each extending from the middle section to a common apex intersecting the longitudinal axis, wherein each adjacent pair of trianguloid surfaces intersects at an edge (e.g., an incurvate edge).

Abstract: In accordance with one embodiment of the present invention, a system for extracting modal parameters of a structure includes an analysis module configured to estimate the modal parameters by computing only a subset of the autospectral matrix of the input data and then solving for the adjoint solution to extract a matrix denominator polynomial. In accordance with another aspect of the invention, orthogonal polynomials are used for the instrumental variables to estimate the matrix polynomial from which the modal parameters are extracted.

Abstract: A payload adapter consists of a body that when hollow includes a plurality of stiffeners—radial and/or circumferential—or alternatively a core for carrying shear loads. The body may include a first annular face sheet, a second annular face sheet and a plurality of stiffeners connecting between the first annular face sheet and the second annular face sheet. The combination of the annular hollow body and the plurality of stiffeners or the same face sheets combined with an in-filled core results in an axial frequency and a lateral (pitch) frequency for the payload adapter that provides superior vibration isolation. Constrained layer damping is incorporated into the design for additional vibration attenuation.