Master of Science / Glass has long been used in glazing applications because of its transparency, stiffness, hardness, resistance to corrosion, and recyclability. Despite these useful features, however, glass is a very brittle material, lacking the ability to usefully absorb energy. Multi-material laminates have been produced as an alternative for glazing applications to improve energy absorption and other functionality requirements. As the demand for these laminates has increased in the construction, automotive, and defense sectors, a need for a more durable system has become apparent. One such example is the laminated glass systems often used in automobiles where two sheets are bonded (laminated) together with a plastic interlayer. Several types of interlayers have been used for these laminated systems, with polyvinyl butyral (PVB) being the most prevalent. A more recently developed interlayer type is thermoplastic polyurethane (TPU), which has the ability to bond to substrates other than glass, making it useful for applications like ballistic-resistant glass laminates, which often involve sheets made of polycarbonate. This study aims to explore the durability of laminated polycarbonate systems by investigating the interaction of environment and TPU viscoelastic behavior on the time-dependent crack growth in these laminates.
The main test utilized is the wedge test, where a wedge is inserted between two polycarbonate adherends bonded together with an interlayer. The wedge causes a debond (a crack) to form. This crack may then grow over time. The crack growth in wedge test specimens with different TPUs is evaluated at various temperature and humidity conditions. A separate test, referred to as dynamic mechanical analysis (DMA), is conducted to determine the thermomechanical properties of the TPUs. These properties are then used to analyze the results of the wedge tests. In addition to different TPU types, the effects of edge seals and surface treatment to improve bonding are compared. Models are used to analyze the resulting data to support the prediction of lifetimes of laminated polycarbonate systems employing the TPUs investigated.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/121028 |
| Date | 27 August 2024 |
| Creators | Riddle, Samuel George |
| Contributors | Engineering Science and Mechanics, Case, Scott W., Bortner, Michael J., Dillard, David A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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