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3D Printing of and Light Scattering in Highly Filled Systems for Mechanical Metamaterials.

Record Type:	Electronic resources : Monograph/item
Title/Author:	3D Printing of and Light Scattering in Highly Filled Systems for Mechanical Metamaterials./
Author:	Shah, Darshil Manish.
Description:	1 online resource (192 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 84-12, Section: B.
Contained By:	Dissertations Abstracts International84-12B.
Subject:	Engineering. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=30317772click for full text (PQDT)
ISBN:	9798379595876

3D Printing of and Light Scattering in Highly Filled Systems for Mechanical Metamaterials.
Shah, Darshil Manish.

3D Printing of and Light Scattering in Highly Filled Systems for Mechanical Metamaterials. - 1 online resource (192 pages)

Source: Dissertations Abstracts International, Volume: 84-12, Section: B.

Thesis (Ph.D.)--University of Massachusetts Lowell, 2023.

Includes bibliographical references

Additive Manufacturing (AM), popularly known as 3D printing, has seen a meteoric rise in both hardware and software technology development and materials proliferation in the last decade, enabling applications not previously feasible. Mechanical metamaterials is an application that has seen growing interest due to the ability to create complex geometries with fine features. Mechanical metamaterials are specifically tailored unit cell array structures with the potential to control wave propagation, as these structures exhibit dynamic behavior not normally observed in homogeneous and natural materials. The performance of a metamaterial depends both on its geometric structure and on its intrinsic material properties, such as density and modulus. Digital Light Processing (DLP)-based 3D printing enables the printing of mechanical metamaterial structures with relatively high resolution. While enabling metamaterial fabrication, photopolymers used in DLP-based 3D printing are limited in their intrinsic properties, thereby limiting the design space of metamaterials. The addition of fillers, especially at higher volume fractions, allows the tailoring of photopolymer material properties. Lowering the density, while maintaining or even increasing the modulus, improves the feasibility for future commercial applications such as acoustic cloaking, sound insulation, and blast wave attenuation. Commercially, however, no low density resins exist for DLP-based 3D printing. Further improvements in metamaterial performance could be achieved by printing the unit cell array with multiple materials with contrasting densities.The main objectives of this dissertation are to (1) prepare highly filled syntactic foam material systems using hollow glass microspheres for DLP-based 3D printing, (2) characterize the light scattering within these filled systems via modeling to predict cured dimensions, and (3) to develop a methodology to fabricate multi-material metamaterial specimens with divergent properties on a single layer.The first part of this dissertation aims to understand the effect of dispersants on the suspension stability of highly filled photopolymer resins over print times and filler homogeneity in the fabricated structure. The material is further characterized to optimize its processing parameters and understand the overall print quality for mechanical metamaterial applications.The addition of hollow-glass microspheres to a photopolymer resin induces light scattering within a three-phase system that is not captured by existing two-phase models. The second topic studied for the first time in this dissertation is the modeling of light scattering using a first-principles approach for systems with three optically active phases, i.e., the surrounding photopolymer resin, the glass shell, and the air core from the hollow-glass filler. Mie scattering theory is utilized to characterize the scattering property of a single hollow-glass sphere. This scattering distribution is input into the Monte Carlo method to scale up the scattering behavior at different volume fractions of hollow-glass microspheres. The model results are compared to fabricated prints.Finally, the third aim of this dissertation is to study the multi-material DLP-based printing of resins with dramatically different processing parameters. An open-source, Autodesk Ember DLP printer is modified to investigate a multi-vat approach for multi-material printing of two resins - a commercially available, high-density, PR48 resin, and a 50 vol% filled, low-density resin with viscosities differing by 3 orders of magnitude. A mechanical metamaterial is fabricated and characterized for its overall frequency response as a demonstration.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798379595876Subjects--Topical Terms:

586835
Engineering.
Subjects--Index Terms:

3D printingIndex Terms--Genre/Form:

542853
Electronic books.

3D Printing of and Light Scattering in Highly Filled Systems for Mechanical Metamaterials.
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504 $a Includes bibliographical references
520 $a Additive Manufacturing (AM), popularly known as 3D printing, has seen a meteoric rise in both hardware and software technology development and materials proliferation in the last decade, enabling applications not previously feasible. Mechanical metamaterials is an application that has seen growing interest due to the ability to create complex geometries with fine features. Mechanical metamaterials are specifically tailored unit cell array structures with the potential to control wave propagation, as these structures exhibit dynamic behavior not normally observed in homogeneous and natural materials. The performance of a metamaterial depends both on its geometric structure and on its intrinsic material properties, such as density and modulus. Digital Light Processing (DLP)-based 3D printing enables the printing of mechanical metamaterial structures with relatively high resolution. While enabling metamaterial fabrication, photopolymers used in DLP-based 3D printing are limited in their intrinsic properties, thereby limiting the design space of metamaterials. The addition of fillers, especially at higher volume fractions, allows the tailoring of photopolymer material properties. Lowering the density, while maintaining or even increasing the modulus, improves the feasibility for future commercial applications such as acoustic cloaking, sound insulation, and blast wave attenuation. Commercially, however, no low density resins exist for DLP-based 3D printing. Further improvements in metamaterial performance could be achieved by printing the unit cell array with multiple materials with contrasting densities.The main objectives of this dissertation are to (1) prepare highly filled syntactic foam material systems using hollow glass microspheres for DLP-based 3D printing, (2) characterize the light scattering within these filled systems via modeling to predict cured dimensions, and (3) to develop a methodology to fabricate multi-material metamaterial specimens with divergent properties on a single layer.The first part of this dissertation aims to understand the effect of dispersants on the suspension stability of highly filled photopolymer resins over print times and filler homogeneity in the fabricated structure. The material is further characterized to optimize its processing parameters and understand the overall print quality for mechanical metamaterial applications.The addition of hollow-glass microspheres to a photopolymer resin induces light scattering within a three-phase system that is not captured by existing two-phase models. The second topic studied for the first time in this dissertation is the modeling of light scattering using a first-principles approach for systems with three optically active phases, i.e., the surrounding photopolymer resin, the glass shell, and the air core from the hollow-glass filler. Mie scattering theory is utilized to characterize the scattering property of a single hollow-glass sphere. This scattering distribution is input into the Monte Carlo method to scale up the scattering behavior at different volume fractions of hollow-glass microspheres. The model results are compared to fabricated prints.Finally, the third aim of this dissertation is to study the multi-material DLP-based printing of resins with dramatically different processing parameters. An open-source, Autodesk Ember DLP printer is modified to investigate a multi-vat approach for multi-material printing of two resins - a commercially available, high-density, PR48 resin, and a 50 vol% filled, low-density resin with viscosities differing by 3 orders of magnitude. A mechanical metamaterial is fabricated and characterized for its overall frequency response as a demonstration.
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538 $a Mode of access: World Wide Web
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653 $a Mie theory
653 $a Carlo, Monte
653 $a Multi-materials
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710 2 $a University of Massachusetts Lowell. $b Mechanical Engineering. $3 2095290
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