ORCID Identifier(s)

0000-0002-4578-1117

Graduation Semester and Year

2017

Language

English

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering

Department

Mechanical and Aerospace Engineering

First Advisor

Kenneth Reifsnider

Second Advisor

Rassel Raihan

Abstract

Composite materials have found their applications in a wide range of industries particularly in the aerospace and automotive sectors. This is because they are comparatively light-weight and provide a much better corrosion and wear resistance as compared to other ceramics and metals. Adhesive bonding can be used to improve the stress distribution between these composite materials. Moreover, adhesive bond decreases the weight and concentration of stresses in the structure. Broadband Dielectric Spectroscopy, BbDS is a robust tool used for analyzing the dielectric properties of a polymer composite. This method can be used to monitor the curing process of the specimen. Alterations in the material systems results in changes in the dielectric spectra of the heterogeneous materials. With increasing service life, the quality of bond decreases thus resulting in interfacial polarization. The objective of this study was to establish BbDS as a NDE method to detect the defect in an adhesive bond. In this case, BbDS is employed to measure the changing dielectric properties throughout the length of the specimen. Thus, two different bonded specimens with varying bond surface quality were made using compression molding – button and single-lap joints. The single-lap joint specimens were then tested for their failure load and a correlation was formulated between the dielectric and mechanical properties. The experimental results were further validated by 2D Finite Element Modeling. In addition to the above research, a brief study was done on inter-ply hybrid composite specimens. In this case, a similar approach was followed wherein, BbDS was used to measure the dielectric properties of two different types of hybrid composite specimens – unidirectional fabric and woven fabric. These specimens were also tested for their load to failure and a correlation was developed between the dielectric and mechanical characteristics.

Keywords

Broadband Dielectric Spectroscopy (BbDS), Composites, Adhesive bonding, Hybrid composites

Disciplines

Aerospace Engineering | Engineering | Mechanical Engineering

Comments

Degree granted by The University of Texas at Arlington

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