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Document Type

Thesis - University Access Only

Award Date

2012

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Jikai Du

Abstract

Composite structure pipes due to their special properties such as high corrosion resistance, light weight and high strength-to-weight ratio have been used in power generation, chemical processing facilities and plumbing for past decades, and continue to grow in acceptance globally. The use of these materials in turn means large scale of manufacture of composite pipes and as a natural extension inspection is required for safety and production efficiency. Ultrasonic guided waves have been recognized as an effective tool for a rapid, long-range inspection of pipes. The understanding of guided wave propagation in hallow cylinders is crucial for nondestructive evaluation of pipelines. Still this technique has several difficulties due to the complex nature of guided waves, material geometry and material properties. This paper presents the use of Finite Element Analysis to evaluate guided wave propagation in thin walled composite cylinder. The principal motivation is to provide tools for performing a guided wave, nondestructive inspection of piping and tubing. ANSYS is adopted to solve the numerical simulation on ultrasonic excitation through the material. At first feasibility of ANSYS is demonstrated by analyzing wave. propagation on a simple two dimensional aluminum plate and results were compared with analytical results prepared by numerical calculations and values from literatures. Then a 3D hallow cylinder model is prepared for two materials; first an Inconel (nickel based alloy) cylinder and second for Aluminum. Results were compared to analytical calculations from previous works and literatures. Good agreement for the 2D plate and isotropic cylinders has motivated the effort to take the practice to the level of dealing with double layer composite cylinder. Wave propagation analysis is made on a double layer composite cylinder composed of a unidirectional fiber/epoxy material wrapped around an aluminum cylinder. Simulations were done with fiber along circumferential and longitudinal direction at different frequencies and wedge angle. To increase simulation efficiency, guided wave at low frequencies is considered. Wave speed is established for each analysis and good agreement is observed with the values from literatures.

Library of Congress Subject Headings

Wave mechanics
Ultrasonic testing
Cylinders
Composite materials
Finite element method

Description

Includes bibliographical references (pages 88-90)

Format

application/pdf

Number of Pages

113

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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