Ph.D. Dissertation Defense by Mark H. Holdhusen
Friday, February 4, 2005
(Dr. Kenneth Cunefare, Chair)
"The State-Switched Absorber Used for Vibration Control of Continuous Systems"
A State-Switched Absorber (SSA) is a device capable of instantaneously changing its stiffness, thus it can switch between resonance frequencies, increasing its effective bandwidth as compared to classical tuned vibration absorbers for vibration control. This dissertation considers the performance of the SSA for vibration suppression of continuous systems, specifically a beam and a plate. The SSA tuning frequencies and attachment point on the continuous body were optimized using a simulated annealing algorithm. It was found that an optimized SSA outperforms and optimized TVA at controlling vibrations of both a beam and a plate. These performance gains were also observed experimentally employing magneto-rheological elastomers to achieve a stiffness change. This dissertation also considers zero strain switching criteria and the maximum work extraction switching rule used by the SSA. The zero strain switching criteria ensures the system remains stable as no energy is added or released across a switch event. The maximum work extraction switching rule is designed to maximize the power dissipated by the absorber, but also guarantees minimization of the motion of the base to which the absorber is attached.