Computational Analysis of Structural Defects in Silica Aerogels
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MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.362
Computational Analysis of Structural Defects in Silica Aerogels Hunter Gore1, Luis Caldera1, Xiao Shen1, and Firouzeh Sabri 1 1
Dept. of Physics and Materials Science, University of Memphis, Memphis, TN. 38152
Abstract
Technological advances in synthesis and preparation of aerogels have resulted in formulations that have the mechanical integrity (while retaining flexibility) to be utilized in a broad range of applications and have overcome the initial brittleness that this class of materials was once known for. Both structural and functional aerogels show a drop in performance when subjected to certain cyclic thermal or impact loading due to the wear and formation of cracks, which reduces their lifespan. Here we present the proof-of-concept of a computational toolset that connects the change in thermal profile to structural failure and degradation. In combination with an appropriate finite element (FEM) solver, we have developed a genetic algorithm that can reconstruct the size and shape of the defective region in silica aerogels given the temperatures from a sensor grid. Results show that a heatmap can be used as the foundation for reconstructing faults and defects in thermally insulating materials. Furthermore, the model developed in this study can be expanded to accommodate other material types. Experimental setup can used to benchmark and refine the computational toolset.
INTRODUCTION There are growing number of practical applications involving luminescence of rare-earth phosphors for remote, precise, and instantaneous sensing applications. The state of the art is the subject of recent efforts [1-5]. Aerogels are being used extensively for thermal insulation purposes and applications [6,7]. Recent efforts to further develop these materials as building blocks for green space has increased substantially over the past decade. Crosslinked silica-based aerogels offer a unique
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combination of light-weight, mechanically strong, and improved thermal insulation capabilities compared to traditional materials such as glass. While most studies have focused on developing cheaper and more transparent aerogels, few studies have investigated the aging effects of silica-based aerogels, and in particular, how mechanical wear and tear affects the thermal response of these aerogels. Furthermore, there is currently no established mechanism to evaluate the thermal behaviour and integrity of the aerogel, while in-use. Here, the authors report on the first-ever investigation on defect modeling using a 2-D temperature map through a combined approach of finite element method and genetic algorithm. The genetic method mimics the evolutionary process in biology with inheritance and mutation from the parents built into th
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