Communications Project

Document Type:Dissertation
Name:Hartono Sumali
Title:A New Adaptive Array of Vibration Sensors
Degree:Doctor of Philosophy
Department:Mechanical Engineering
Committee Chair: Harley H. Cudney
Committee\ Members:
Keywords:modal analysis, algorithm, eigenvectors
Date of defense:July 3, 1997
Availability:Release the entire work for Virginia Tech access only.
After one year release worldwide only with written permission of the student and the advisory committee chair.


The sensing technique described in this dissertation produces modal coordinates for monitoring and active control of structural vibration. The sensor array is constructed from strain-sensing segments. The segment outputs are transformed into modal coordinates by a sensor gain matrix.

An adaptive algorithm for computing the sensor gain matrix with minimal knowledge of the structure’s modal properties is proposed. It is shown that the sensor gain matrix is the modal matrix of the segment output correlation matrix. This modal matrix is computed using new algorithms based on Jacobi rotations. The procedure is relatively simple and can be performed gradually to keep computation requirements low.

The sensor system can also identify the mode shapes of the structure in real time using Lagrange polynomial interpolation formula.

An experiment is done with an array of piezoelectric polyvinylidene fluoride (PVDF) film segments on a beam to obtain the segment outputs. The results from the experiment are used to verify a computer simulation routine. Then a series of simulations are done to test the adaptive modal sensing algorithms. Simulation results verify that the sensor gain matrix obtained by the adaptive algorithm transforms the segment outputs into modal coordinates.

List of Attached Files

chapter1.PDF chapter2.PDF chapter3.PDF
chapter4.PDF chapter5a.PDF chapter5b.PDF
chapter6.PDF chapter7.PDF end.PDF

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