Advanced sensing techniques for active structural acoustic control

• Main Author: Clark, Robert L. Jr.
• Other Authors: Mechanical Engineering
• Format: Others
• Language: en
• Published: Virginia Tech 2014
• Subjects: LD5655.V856 1992.C624; Acoustical engineering; Noise control; Piezoelectric transducers
• Online Access: http://hdl.handle.net/10919/37880; http://scholar.lib.vt.edu/theses/available/etd-05222007-091351/

This study presents a basis for the analytical and experimental procedures as well as design techniques required in achieving adaptive structures 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. Structural acoustic control was achieved with piezoelectric actuators bonded to the surface of the test structure. The primary focus of this work was devoted to studying alternative sensing techniques in feed forward control applications. Specifically, shaped distributed structural sensors constructed from polyvinylidene fluoride (PVDF), distributed acoustic near-field sensors constructed from PVDF, and accelerometers were explored as alternatives to microphones which are typically implemented as error sensors in the cost function of the control approach. The chosen control algorithm in this study was the feed forward filtered-x version of the adaptive LMS algorithm. A much lower level of system modelling is required with this method of control in comparison to state feedback control methods. As a result, much of the structural acoustic coupling (i.e. system modelling) must be incorporated into the sensor design. === Ph. D.