Dynamic mechanical analysis and computer simulation of polyurea aerogels

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Prokopf, Victoria Ann
Missouri University of Science and Technology
Aerospace Engineering
thesis / dissertation description
"Historically, the use of aerogels has been limited due to their poor mechanical properties. However, polyurea aerogels have proven to be mechanically strong under quasi-static conditions. Polyurea aerogels can be created by filling molds of the desired shape with a liquid solution that then creates a solid gel filled with liquid. The liquid can be removed from the gel by supercritical drying. This thesis outlines dynamic testing as well as simulation for polyurea aerogels.Testing has been conducted in dynamic tension and bending for densities of polyurea aerogels ranging from 0.12 g/cm3 to 0.31 g/cm3. In most cases, the mechanical properties were minimally affected when tested over a range of frequencies. In tension the previously observed increase of stiffness with density was not present. In this case the 0.17 g/cm3 has the lowest storage modulus.Simulations were performed to develop a better understanding of structure-property response of highly porous polyurea aerogels. Micro-scale effects such as particle stiffness, bond strength, and particle frictional coefficients were incorporated into the macro-scale structure-property relationship for the prediction of the Young's modulus. Compression simulations were performed and compared to the corresponding experiment"--Abstract, page iii.