Date of Award

Spring 2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Committee Director

Onur Bilgen

Committee Member

Thomas E. Alberts

Committee Member

Drew Landman

Abstract

Bistability is the property of structures showing the ability to attain two statically stable states. Due to dynamic and static advantages such as no energy demand at stable positions and providing higher deflections compared to a monostable structure, bistability may be appealing in control surface design for aircraft structures and load alleviation for wind turbine blades. The dynamics of bistable structures is nonlinear because of the snap-through occurring during the cross-well oscillation between two stable states. A new control strategy called hybrid position feedback control is developed based on the conventional positive position control to exploit linear dynamics of bistable structures around stable equilibrium positions.

In this thesis, complementary stability, performance and energy analysis of bistable structures controlled by the hybrid controller are investigated using numerical time domain and frequency methods. The stability regions, energy variance by parameters, and the operational regions providing state transition are determined. As a result of the analyses, two alternative design options are proposed and necessary stability regions are indicated.

In addition, experimental analysis is conducted on an unsymmetric cross-ply bistable composite plate to show the feasibility of the hybrid control strategy. Various analyses such as stability and energy consumption are performed.

ISBN

9781339893877

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