4D Printed Auxetic Structures with Tunable Mechanical Properties

A Master of Science thesis in Mechanical Engineering by Mohammad Hani Yousuf entitled, “4D Printed Auxetic Structures with Tunable Mechanical Properties”, submitted in June 2019. Thesis advisor is Dr. Wael Abuzaid. Soft and hard copy available.

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Main Author: Yousuf, Mohammad Hani (author)
Format: doctoralThesis
Published: 2019
Subjects:
Online Access:http://hdl.handle.net/11073/16481
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author Yousuf, Mohammad Hani
author_facet Yousuf, Mohammad Hani
author_role author
dc.contributor.none.fl_str_mv Abuzaid, Wael
dc.creator.none.fl_str_mv Yousuf, Mohammad Hani
dc.date.none.fl_str_mv 2019-09-03T09:06:59Z
2019-09-03T09:06:59Z
2019-06
dc.format.none.fl_str_mv application/pdf
dc.identifier.none.fl_str_mv 35.232-2019.35
http://hdl.handle.net/11073/16481
dc.language.none.fl_str_mv en_US
dc.subject.none.fl_str_mv 4D printing
Shape memory polymers
Recovery strains
Auxetic structures
Cellular solids
Tunable properties
Shape memory polymers
Mechanical properties
Elastic properties
Additive manufacturing
dc.title.none.fl_str_mv 4D Printed Auxetic Structures with Tunable Mechanical Properties
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/doctoralThesis
description A Master of Science thesis in Mechanical Engineering by Mohammad Hani Yousuf entitled, “4D Printed Auxetic Structures with Tunable Mechanical Properties”, submitted in June 2019. Thesis advisor is Dr. Wael Abuzaid. Soft and hard copy available.
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identifier_str_mv 35.232-2019.35
language_invalid_str_mv en_US
network_acronym_str aus
network_name_str aus
oai_identifier_str oai:repository.aus.edu:11073/16481
publishDate 2019
repository.mail.fl_str_mv
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spelling 4D Printed Auxetic Structures with Tunable Mechanical PropertiesYousuf, Mohammad Hani4D printingShape memory polymersRecovery strainsAuxetic structuresCellular solidsTunable propertiesShape memory polymersMechanical propertiesElastic propertiesAdditive manufacturingA Master of Science thesis in Mechanical Engineering by Mohammad Hani Yousuf entitled, “4D Printed Auxetic Structures with Tunable Mechanical Properties”, submitted in June 2019. Thesis advisor is Dr. Wael Abuzaid. Soft and hard copy available.Additive manufacturing (i.e., 3D printing) has revolutionized the entire design cycle from prototyping, machining, and assembly. The majority of the materials suitable for 3D printing result in rather rigid structures with a fixed set of properties. Four-dimensional printing (4D printing) addresses this limitation through the use of active and smart materials during 3D printing. The careful selection of structural design and suitable stimulus-activated smart material enables a unique set of shapes and properties to be programmed and achieved. This deviation from rigid structures with a fixed set of properties enables novel and unique applications in robotics, deployable structures, biomedical, and aerospace industries. The current work is focused on an interesting class of structures, 2D auxetic cellular solids, which exhibit distinctive mechanical properties (e.g., negative Poisson’s ratio) due to their carefully designed porous structure. 4D printing of such structures using smart materials allows for changes in the unit cell shape and dimensions to be made and thus resulting in tunable structural stiffness, Poisson’s ratio, and rigidity. This work aims to experimentally investigate the tunability of stiffness and Poisson’s ratio in 4D printed auxetic structure through utilization of programming and shape recovery properties found in Shape-Memory Polymers (SMP). Auxetic honeycomb structures with tunable mechanical properties were successfully manufactured and evaluated in this work. The attained structural stiffness was tuned in the range of 0.179-0.242 kN/mm while the Poisson’s ration was controlled from -0.33 up to even positive magnitudes of +0.69. This wide range of elastic properties was obtained from a single structure programmed to different deformation levels. Experimental evaluation of 4D printed SMP structures under constant cyclic programming/recovery conditions induced residual strains which consequently affected the mechanical properties by degrading the Poisson’s and structural stiffness. The magnitude of induced residual strains depend on the level of applied deformation during programing and the number of applied programing/recovery cycles. At the local level, full-field measurements revealed the localization of strains within the complex heterogeneous structure of the axially loaded auxetic honeycomb samples.College of EngineeringDepartment of Mechanical EngineeringMaster of Science in Mechanical Engineering (MSME)Abuzaid, Wael2019-09-03T09:06:59Z2019-09-03T09:06:59Z2019-06info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdf35.232-2019.35http://hdl.handle.net/11073/16481en_USoai:repository.aus.edu:11073/164812025-06-26T12:25:31Z
spellingShingle 4D Printed Auxetic Structures with Tunable Mechanical Properties
Yousuf, Mohammad Hani
4D printing
Shape memory polymers
Recovery strains
Auxetic structures
Cellular solids
Tunable properties
Shape memory polymers
Mechanical properties
Elastic properties
Additive manufacturing
status_str publishedVersion
title 4D Printed Auxetic Structures with Tunable Mechanical Properties
title_full 4D Printed Auxetic Structures with Tunable Mechanical Properties
title_fullStr 4D Printed Auxetic Structures with Tunable Mechanical Properties
title_full_unstemmed 4D Printed Auxetic Structures with Tunable Mechanical Properties
title_short 4D Printed Auxetic Structures with Tunable Mechanical Properties
title_sort 4D Printed Auxetic Structures with Tunable Mechanical Properties
topic 4D printing
Shape memory polymers
Recovery strains
Auxetic structures
Cellular solids
Tunable properties
Shape memory polymers
Mechanical properties
Elastic properties
Additive manufacturing
url http://hdl.handle.net/11073/16481