THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, May 3, 2022

11:00 AM  

in MRDC 3515

& via

Microsoft Teams

https://teams.microsoft.com/l/meetup-join/19%3ameeting_OWNjOWM2MTYtMWJhYi00ZDliLWE4ZmMtZWRiNDM3MjNiMTQ5%40thread.v2/0?context=%7b%22Tid%22%3a%22482198bb-ae7b-4b25-8b7a-6d7f32faa083%22%2c%22Oid%22%3a%229922d0c4-e836-4c95-a671-ea50c4333af9%22%7d 

will be held the

DISSERTATION DEFENSE

for

Andrew Boddorff

“Role of Heterogeneities on the Shock Compression Response of Additively Manufactured Highly Solids Loaded Polymer Composites and Two-Layered Bimetallic Alloys”

Committee Members:

Prof. Naresh Thadhani, Advisor, MSE

Prof. Blair Brettmann, CHEM/MSE

Prof. Meisha Shofner, MSE

Prof. Min Zhou, ME

Mrs. Karen Taminger, NASA

Abstract:

In this work, the effects of process inherent heterogeneities across multiple length scales on the dynamic shock compression behavior of additively manufactured highly solids loaded polymer composites and bilayered metallic structures are investigated. The polymer composite material consists of three different particles, two inorganic and one organic, with different sizes encapsulated in an organic binder. The bilayered metallic structure consists of GRCop-84 and Inconel® 625 layers with varying interface geometries.

AM-fabricated materials develop process inherent heterogeneities that result in hierarchical, directional structures. The exploration of how process-inherent microstructures of AM materials behave under shock compression is in the early stages. Proper understanding of the roles of the heterogeneities on the shock compression response can lead to better prediction and utilization of these complex materials in extreme conditions.

In order to address the role of heterogeneities arising from complex, AM fabricated materials on their shock compression and dynamic tensile behavior, the highly solids loaded polymer composites and bilayered metallic structures are investigated using plate-on-plate impact experiments. The use of multiple PDV probes at different locations on the highly solids loading polymer composite samples resulted in diverse velocity profile features that arise from the interaction of the shock wave with particles and voids. CTH simulations of the impact of highly solids loaded polymer composites show the existence of a range of shock states within the composites and differences in the shock thicknesses by sample orientation. Plate-on-plate impact experiments on the bilayered metallic structures reveal differences in the dynamic tensile and spall failure response influenced by the interface geometry, with planar interface geometry samples undergoing failure primarily along the wavy interface, while the slanted interface geometry samples exhibit failure along the interface as well as in constituent materials. The observation of the role of heterogeneities at different length scales and in different additively manufactured material systems on the shock compression response was made possible with the use of multiple interferometry probes and novel optomechanical sensors.