Date of Award

12-2022

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Aerospace, Physics, and Space Sciences

First Advisor

Mary Helen McCay

Second Advisor

James R. Brenner

Third Advisor

Tracy Colwell

Fourth Advisor

David C. Fleming

Abstract

Adhesively bonded structures are used in many high-tech industries such as aerospace, automotive, and defense. The application of these joints using composite adherends has increased in recent years because of improved strength-to-weight ratio, design flexibility, and lower concern for corrosion. Quality acceptance of these structures largely depends on reliability and durability which includes influence of environmental service conditions on long-term behavior. Characterization of long-term behavior presents a difficult challenge to those involved in material selection and design due to the long service life of the joint compared to the development time available and complexity of the degradation mechanisms. Therefore, different testing approaches are needed to address aging of bonded systems. First, an introduction to design, testing, and analysis of adhesively bonded composite structures is reviewed, along with an in-depth assessment of degradation mechanisms related to bonded composite joints. Next, current research, methodologies, and knowledge gaps on accelerated aging of structurally bonded composites involving the Arrhenius Reaction Rate theory are discussed. Finally, an empirical model and case study is proposed and demonstrated using Arrhenius methodology, statistically designed experimental techniques, and verification methods. This proposed model is intended to provide guidance for predicting and verifying long-term behavior of adhesively bonded composite aerospace structural joints in an ambient storage environment to aid in material selection during development.

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