Master's Thesis Defense

Michael Hartin

(Faculty Advisor: Cristina Riso)

Wednesday, December 3

11:30 a.m.

Guggenheim 442

Abstract:

This thesis introduces a novel output-based approach for predicting limit-cycle oscillations caused by freeplay, a stiffness nonlinearity resulting in no or highly reduced restoring elastic effects within specific motion ranges of actuated structures. This nonlinearity can affect moving parts of aerospace vehicles, such as control surfaces or tilting propellers and rotors, as well as other engineering systems that feature components in relative motion. The resulting self-excited periodic oscillations can degrade system performance and induce structural damage, fatigue, or failure. These issues require computationally efficient and accurate methods to predict the onsets and amplitudes of freeplay-induced limit-cycle oscillations early in the design phase.

Committee:
Dr. Cristina Riso (advisor), School of Aerospace Engineering
Dr. Graeme Kennedy, School of Aerospace Engineering
Dr. Keegan Moore, School of Aerospace Engineering