Committee Members:

Prof. Naresh Thadhani, Advisor, MSE

Prof. Min Zhou, ME

Prof. Blair Brettmann, MSE/CHBE

Prof. Arun Gokhale, MSE

Brian Jensen, Ph.D., Los Alamos National Lab

""Characterization and Effects of Heterogeneities on Shock Compression Response in Additively Manufactured High-Solids Loaded Polymer Composites""

Abstract:

High-solids loaded polymer composites contain several hierarchies of heterogeneities that are of interest for use as, for example, ceramic green bodies or energetic crystals embedded in a polymermatrix. The recent and rapid growth of additive manufacturing (AM) and the engineering need formore complex geometries and individualized products has led to a surge of interest in fabricating high-solids loaded particle composites. AM via direct ink write extrusion processes introducesfurther complexity in fabrication of composites due to formation of process-inherentheterogeneities such as particle aggregation or porosities. The microstructure of such materialsvaries across different length scales, resulting in processing and mechanical behavior that is oftendifficult to control and predict.

The shock-compression behavior of heterogeneous particle-filled polymer composites ofteninvolves complex interactions, which can make it difficult to predict their dynamic mechanicalproperties. The shock-compression behavior is often dominated by mesoscale defects (includingporosity) or interactions of the shock wave with interfaces and particulates. Traditional diagnosticmethods, such as velocity interferometry, enable temporally-resolved measurements, but arelimited in spatial resolution and generally provide a volume-averaged response. Spatially resolvedmeasurements are necessary to measure the shock compression properties and provide sufficientinformation regarding the mesoscale processes which dominate performance of such materials.The goals of the proposed work are: to quantitatively characterize additively manufactured particlecomposite microstructures, determine their shock compression response, and correlate theobserved shock response with the microstructural characteristics of the process inherentheterogeneities.