DOI

10.17077/etd.dpegr0hb

Document Type

Dissertation

Date of Degree

Fall 2017

Degree Name

PhD (Doctor of Philosophy)

Degree In

Civil and Environmental Engineering

First Advisor

Rahmatalla, Salam

First Committee Member

Arora, Jasbir S.

Second Committee Member

Bhatti, M. Asghar

Third Committee Member

Lu, Jia

Fourth Committee Member

Swan, Colby C.

Abstract

The identification of the physical parameters (mass, stiffness, and damping) of structural, mechanical, and biomechanical systems is a major challenge in many applications, especially when dealing with old systems and biological systems with heavy damping and where environmental noises are presented. This work presents a novel methodology called eigenvector phase correction (EVPHC) to solve for the physical parameters of structural and biomechanical systems even with the existence of a significant amount of noise. The method was first tested on structural/mechanical systems and showed superior results when compared with an iterative method from the literature. EVPHC was then developed and used to identify the physical parameters of supine humans under vertical whole-body vibration. Modal parameters of fifteen human subjects, in the supine position, were first identified in this work using experimentation under vertical whole-body vibration. EVPHC was then used to solve an inverse modal problem for the identification of the stiffness and damping parameters at the cervical and lumbar areas of supine humans. The results showed that the resulting physical parameters were realistically close to those presented in the literature. The proposed human model was able to predict the time histories of the acceleration at the head, chest, pelvis, and legs very closely to those of the experimental measured values. A scaling methodology is also presented in this work, where an average human model was scaled to an individual subject using the body mass properties.

Keywords

damped system, eigenvector noise, modal analaysis, multi-body dynamics, optimization, transfer function

Pages

xviii, 154 pages

Bibliography

Includes bibliographical references (pages 151-154).

Copyright

Copyright © 2017 Guandong Qiao

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