Date of Award

2005

Document Type

Thesis

Degree Name

Master of Science in Material Science Engineering (MSMatSE)

Department

Materials Science

First Advisor

D r. Abdullah Al-Khanbashi

Second Advisor

Kiristoper Gamstedt

Third Advisor

Adel Hamami

Abstract

The aim of this research was to study the effect of bond thickness on the fracture energy and the lifetime of an adhesively bonded system and develop a model to predict the lifetime of adhesive joints. An approach based on fracture mechanics was employed to assess aluminum/epoxy bond lifetime. An experimental investigation was carried out using double cantilever beam (DCB) specimens with various bond thicknesses under mode 1.

This study describes an approach to predict the rate of crack propagation using Paris' power law. The approach used elevated temperatures to accelerate the crack propagation under constant loads. The elevated temperatures were kept below the glass transition of the adhesive. The general idea was to apply a constant load below the critical value to allow for measurable slow crack propagation. The fracture energy of the bonded joints was evaluated using both simple beam and beam on elastic foundation analyses. A simple model was proposed to predict the variation of the two kinetic parameters of Paris' law as a function of bond thickness. A model was developed, which would enable crack propagation to be modeled and hence the lifetime of adhesive joints to be predicted.

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