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Showing 1 to 20 of 21 for “"ASAC"”.
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On the use of modern control theory for active structural acoustic control
… of Active Structural Acoustic Control (ASAC) of simple structures radiating acoustic energy into light or heavy fluid mediums is discussed in this dissertation. ASAC of a baffled, simply-supported plate subject to mechanical disturbances is investigated. For the case of light fluid …
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System Identification and Optimization Methodologies for Active Structural Acoustic Control of Aircraft Cabin Noise
… techniques. Active Structural Acoustic Control (ASAC) has shown much promise for reducing interior cabin noise in aircraft by applying control forces directly to the fuselage structure. Optimal positioning of force actuators for ASAC presents a challenging problem however, because a detailed …
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Active control of a coupled plate-cylinder system
… system. The Active Structural Acoustic Control (ASAC) approaches include the control of the acoustic pressure in one or several directions of radiation, the control of the total radiated power, the control of the power radiated in a sector and the control of selected components associated with …
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Active control of broadband acoustic radiation from structures
Active Structural Acoustic Control (ASAC) has been previously demonstrated for systems excited by single and multiple frequency disturbances. This work is an extension of ASAC techniques to the control of sound radiation from structures excited by a disturbance with broadband frequency content. An …
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Untersuchung des Argininmetabolismus und dessen Regulation in Corynebacterium glutamicum ATCC 13032
… RNA (asRNA) gegenüber dem 5’ Ende von argC, die AsaC genannt wurde. Transkriptionelle Analysen mit einer ΔasaC Mutante zeigten, dass die Transkription von argC negativ durch die asRNA beeinflusst wird und dass der Wirkmechanismus von AsaC transkriptionelle Interferenz ist. Aus diesen Ergebnissen …
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Demonstration of active structural acoustic control of cylinders
… is called Active Structural Acoustic Control (ASAC) (Fuller, 1987). Sensors are implemented using piezoelectric film, and actuators are implemented using piezoceramic material. Both analog and digital noise cancellation control algorithms are used to reduce the noise emission from the cylinder. …
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Optimization of transducers for active structural acoustic control of complex structures using numerical techniques
… studies of Active Structural Acoustic Control (ASAC) on a simply supported plate with various discontinuities such as point mass, line mass, and spring mass systems. These system models were harmonically excited by an off resonance point force of 550 Hz and controlled by piezoceramic actuators. …
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Design of Active Structure Acoustic Control Systems Using Eigenassignment Approach
Active structural acoustic control (ASAC) in conjunction with the adaptive feedforward control has been proved to be an efficient practical approach to reduce structure-borne sound. ASAC works on the principles of reducing the vibration amplitude of the structure (modal reduction), as well as …
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Advanced Time Domain Sensing For Active Structural Acoustic Control
… decade. In Active Structural Acoustic Control (ASAC), the minimization of sound radiation is achieved by modifying the response of the structure through structural inputs rather than by exciting the acoustic medium (Active Noise Control, ANC). The ASAC technique often produces global far-field …
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Advanced sensing techniques for active structural acoustic control
… for active structural acoustic control (ASAC). Test structures studied in this work included a baffled simply supported beam and a baffled simply supported plate which were subjected to a harmonic input disturbance created physically with a shaker and modelled by a point force input. …
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A regression-based approach for simulating feedfoward active noise control, with application to fluid-structure interaction problems
… context of active structural-acoustic control (ASAC), in which sound radiating from a vibrating structure is controlled by applying time-harmonic vibrational inputs directly on the structure. First, a feedforward control simulation is developed for a submerged spherical shell using both …
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Design of, and initial experiments with, a MIMO plate control testbed
… and standard comparison site for AVC and ASAC and is an extension of previous SIMO control investigations which used accelerometers and shakers. This portion of the development process of the MIMO plate control testbed is concerned with actuator and sensor materials and architecture, …
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Structural-acoustic design and control of an integrally actuated composite panel
… to active structural-acoustic control (ASAC). To quantify the comparison, designs based on classical low-authority feedback, optimal feedback, and x-filtered LMS feedforward techniques are presented. The results lend insight into the inherent limitations and advantages of each approach …
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The optimal design of transducers for active control of multiple-frequency structural sound radiation
… problem of active structural acoustic control (ASAC) of radiation from elastically supported plates under multiple-frequency excitation. The control is achieved by use of piezoelectric (PZT) actuators. An optimization procedure is developed to find the optimal locations of actuators with which …
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Optimum design for feedforward structural-acoustic control of complex structural systems
… feedforward Active Structural Acoustic Control (ASAC) systems for complex structures and disturbances is presented. The approach consists in a multi-level optimization procedure. The upper level part is carried out in the modal domain, where the optimum modal control forces and modal error sensor …
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MODELING AND DESIGN OF A SMART DOUBLE-PANEL SYSTEM FOR THE CONTROL OF SOUND TRANSMISSION INTO AIRCRAFT CABIN
… an effective active structural acoustic control (ASAC) method. This research presents the development and application of an effective methodology of an active structural acoustic control system for the reduction of low frequency sound transmission through an aircraft double-panel sidewall …
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Active structural acoustic control of double panel systems including hierarchical control approaches
… Results of active structural acoustic control (ASAC) applied to double panel systems indicated that the best control performance was exhibited by a double panel system controlled by PZT control actuators mounted on a sandwich board radiating plate. The sandwich board radiating plate double panel …
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Optimum Actuator Grouping in Feedforward Active Control Applications
… grouping and active structural acoustic control (ASAC) of a simply-supported beam excited with a broadband disturbance. Three PZT actuators are mounted on the beam structure to control the wavenumber components corresponding to five radiation angles. The propagation angles are selected to …
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Active control of automobile cabin noise with conventional and advanced speakers
… (ANC) and Active Structural Acoustic Control (ASAC) techniques are being applied to problems stemming from power train noise and road noise (noise due to the interaction of the tires with the surface of the road). Due to the low frequency characteristics of these noise problems, large acoustic …
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Active structural acoustic control of aircraft interior flow noise via the use of active trim panels
Modem jet aircraft interior noise can be categorized into two main types: tonal noise caused by engine imbalance or blade passage, and mid frequency broadband noise resulting from turbulent flow. This project addresses aircraft interior flow noise caused by a flow separation over the crown of the …
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