Electronic Theses and Dissertations

Date of Award

1-1-2020

Document Type

Dissertation

Degree Name

Ph.D. in Physics

First Advisor

Joel Mobley

Second Advisor

Likun Zhang

Third Advisor

Wayne E Prather

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

The Nondestructive Evaluation (NDE) of cylindrical containers is of critical importance because of their ubiquity in industrial applications. However, there is a paucity of research in the literature on NDE studies of solid cargo inside cylindrical containers. This dissertation consists of three connected projects investigating the application of linear and nonlinear Acoustic Resonance Spectroscopy (ARS) to the NDE of solid cargo inside sealed cylindrical containers. In these projects, the container of interest varied from extremely complicated to very simplified, and the studies extended from applied to basic physics problems. The first study was focused on an empty Transnuclear-32 (TN-32) nuclear cask for spent fuel (5.1 m in height and 2.5 m in diameter), the vibrational modes were measured and compared to Finite Element Analysis (FEA) of a TN-32 cask. The modal structural changes due to various loadings of spent fuel were also investigated through FEA. Because of the practical difficulties of introducing damage on the spent fuel inside a full-scale TN-32 cask, a 1:6 scaled lab cask was manufactured. First, modes of the lab cask were measured, simulated, and compared to the TN-32 cask. Second, ARS measurements were conducted on the lab cask with various configurations of mock-up fuel assemblies, debris, and empty state in each of the 32 basket slots. The integrity of the mock-up fuel assemblies can be estimated by the metrics developed in this work. However, the signatures of a damaged versus missing assembly were not clearly resolved. To further improve the sensitivity, Nonlinear ARS (NARS) was used to investigate the contact nonlinearity between the debris and the container. A 20 cm-tall cylinder loaded with various types of spheres was used as a simplified experimental model. The NARS results showed unique characteristics than that has been reported in the literature. The experimental results were successfully modeled with a contact loss phenomenological model, which was then implemented in FEA. NARS was able to estimate the total mass of the spheres regardless of the material and radius. In summary, this dissertation demonstrates the feasibility of applying ARS and NARS on the NDE of solid cargo inside cylindrical containers.

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