Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

First Advisor

Ronald L. Bagley, PhD


A modified form of the standard linear quadratic regulator LQR cost functional is used to optimally blend active vibration control and passive structural damping, whether viscous or viscoelastic. Viscoelastic damping is first modelled by a standard linear model, and then by a fractional derivative model. For the viscous damping case and the classically modelled viscoelastic damping case, a sub-optimal closed form solution is derived that is independent of the initial conditions. An iterative technique that minimizes the average value of the cost functional and one that minimizes the maximum value are developed. Both techniques are applicable to viscous and viscoelastic damping and are independent of the initial state. The advantages and disadvantages of the different solution techniques are given with respect to computation requirements and performance. Several numerical examples illustrate the similarities of and differences between the various techniques.

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DTIC Accession Number



The author's Vita page is omitted.