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The equivalent time temperature method (ETT) is a novel extension of the equivalent time method. ETT is developed in this work to deal with time-temperature shifting of long-term polymer and polymer composite creep data, including the effects of physical aging at nonuniform temperature. Modifications to classical testing methods and protocols are presented to obtain accurate and repeatable data that can support long-term predictions with nonuniform temperature conditions through time. These techniques are used to generate momentary Time temperature superposition (TTSP) master curves, temperature shift factor rates, and aging shift factor rates. Novel interpretation and techniques are presented to deal with the coupled age-temperature behavior over long times. Validation of predictions against over 20,000 Hr of long-term data in field conditions is presented.

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Characterization of Self-Healing Composite Materials Kevin John FordDamage occurs in almost every composite material in the form of microcracks that develop in the epoxy matrix that binds the fibers together. Researchers at the University of Illinois Urbana Champaign have recently developed a method to reverse the effects of, or heal, damage in the epoxy matrix. Their in-situ self-healing system uses embedded microcapsules and a catalyst that trigger a romp reaction in an effort to rebond the microcracks. Several models have been developed in an effort to predict how a composite laminate damages. One model in particular, the Continuous Damage Mechanics model, CDM that has been developed at West Virginia University uses material properties that are easily obtained from standard ASTM and ISO testing methods. The CDM model has been extended at West Virginia University to incorporate the effects of a self-healing system to develop a Continuous Damage and Healing Mechanics model, CDHM. In this work, a testing procedure to characterize the autonomic healing of polymer matrix composites is outlined, as well as the regenerative effects of the self-healing system. The capability of the CDHM model to predict the material properties of the self-healing system is also addressed. The CDHM model is validated with experimental results for various laminates fabricated out of E-glass/epoxy. iii DEDICATION This disertation is dedicated to my family. Your support and encouragement have meant a lot to me over the years and I am forever grateful. Thank you!iv ACKNOWLEDGEMENTS I would like to thank my committee members Dr.

Physical aging of polyvinyl chloride, high-density polyethylene, and polyester reinforced with polyester fibers specimens have been investigated. These materials are commercially available and are currently used in trenchless relining of sewer pipes. The analysis uses the effective-time theory and time-temperature superposition (TTSP) methods proposed by Struik, as well as variations of these methods, as proposed by Chai and McCrum, Guerdoux et al. and others. The creep data generated by this study show that the time-dependant creep properties of these materials can be modeled within experimental error with slight changes to the above methods. To predict the creep behavior of full-scale specimens; these properties were then shifted from their testing age and temperature to the testing age and temperature of the full-scale specimens. It was shown that a rotation, along with a horizontal shift of the aging data, is needed to obtain the ageing parameter of the materials. iii DEDICATION This thesis is dedicated to my grandparents, the late John and Anna Kondik and the late Ross and Martha Ford. Without their influence in my life this would not have been possible, thanks.