Date of Award
Master of Science
The increasing use of composite materials in many industries such as aerospace, automotive, and civil industries has increased the need for the development of effective techniques to detect defects in the bondlines of adhesive joints in composite structures. Currently, composite structures used in commercial applications such as modern aircraft use mechanical fasteners in redundancy to adhesive bonds to ensure structural integrity due to a lack of methods to reliably detect defects in the bondline of composite structure. As such, this thesis facilitates the development of nondestructive evaluation techniques for detecting bondline defects by using finite element (FE) modeling to simulate the effects of disbond defects caused by contamination of the bondline. These models were developed for single-lap joint specimens made of metal, composite, and dissimilar materials (metal bonded with composite) with contamination induced disbonds. The created FE models were used to generate whole-field strain data for single-lap joints under tensile loading. This generated strain data was then used to provide a model for evaluating and interpreting experimental strain measurements captured by digital image correlation (DIC). Finally, conclusions were drawn outlining the observed capability of strain measurement in the evaluation of bondline contamination in single-lap joints.
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