Civil Engineering ETDs

Publication Date

Spring 5-11-2024

Abstract

Dynamic testing of systems is used to characterize the relationship between inputs and outputs using frequency response functions (FRFs). Multiple input and multiple output (MIMO) techniques are crucial for realistic representation. In MIMO tests, environmental conditions are replicated by inverting the FRF matrix for input estimation. Steps include system identification, FRF inversion, input estimation, and input application. Each of these steps are nontrivial and require careful attention. Error sources manifest as error between desired and experimental outputs. Significant efforts to minimize this error exist, yet literature lacks a formal understanding of their origins. This research focuses on 3 of these error sources; uncertainty in the FRFs, described by FRF variability error (FRFVE); the frequency to time domain conversion of the inputs, described by random process realization error (RPRE); and matrix inversion error. This research proposes 2 error prediction frameworks that account for these sources. The first, the approximate error prediction method (AEPM), was initially used to account for errors due to FRFVE and RPRE. The second, the exact error prediction method (EEPM), incorporates inversion error and does not make simplifying assumptions used in the AEPM. Each was applied to MIMO tests and accuracy in the error prediction was quantified and compared. Both methods were found to be effective in varying degrees in predicting errors. It is proposed that future research applies the method to more complex and realistic tests, and findings used to develop more informed specifications and improve MIMO testing capabilities.

Keywords

vibration, testing, error prediction, structural dynamics, multiple-input multiple-output

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Fernando Moreu

Second Committee Member

Rafiqul Tarefder

Third Committee Member

John Pott

Fourth Committee Member

Nicholas Wierschem

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Available for download on Monday, May 11, 2026

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