Civil Engineering ETDs

Publication Date

Fall 12-16-2024

Abstract

Sources of nonlinearities in structures can introduce many phenomena that cannot be characterized by linear analysis such as bifurcations leading to the jump phenomena and isolated resonance branches. These phenomena can often give rise to complex behaviors and lead to extreme responses that can potentially cause damage to structures. It is therefore critical to advance numerical and experimental tools to better characterize these behaviors.

This dissertation explores the use of fixed frequency voltage control tests to stabilize strongly nonlinear structures and detect isolated resonance branches. This open-loop control scheme exploits electromechanical shaker dynamics through the force dropout phenomena and voltage continuation to measure stabilized S-curves. Shaker-structure models were developed to perform fixed frequency voltage control using Multi-Harmonic Balance simulations and conduct pre-test predictions and analyses. Fixed frequency voltage control tests were also performed experimentally on a strongly nonlinear vibro-impact structures to demonstrate stabilization and measurements of isolated resonance curves.

Keywords

Experimental nonlinear dynamics, impact nonlinearity, fold bifurcations, experimental stability, open loop control

Document Type

Dissertation

Language

English

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

First Committee Member (Chair)

Fernando Moreu

Second Committee Member

Robert Kuether

Third Committee Member

Rafiqul Tarefder

Fourth Committee Member

Nicholas Wierschem

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