George, Eliot
(2016)
Investigation of Variable Stiffness Based Polymer Morphing Structures.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Morphing structures have a multitude of potential applications in many engineering fields. Control surfaces for aircraft, pumps and valves for artificial organs or any application where a complex motion is required and can benefit from incorporating a morphing structure. The ability of a morphing structure to change its shape or configuration can potentially allow designs and functionality that would be impossible to realize without morphing. The focus of this thesis is to investigate the feasibility and operation of a structural shape morphing structure. Structural shape morphing is defined as shape change through material modulus changes. This allows fewer actuators, fewer moving parts and lower energy consumption to effect the same change in configuration as a traditional shape change structure. The morphing structure examined was designed and created specifically for this work and is composed almost entirely of polymer materials. The design utilizes electrical voltage to control the structural stiffness and motion of the structure independently. A review of literature covering fabrication and modeling in morphing structures, polymer actuators, variable modulus materials and variable stiffness structures is presented. A conceptual design for a shape morphing structure is fabricated and refined and an analytical model is developed for the structure to predict its response to applied voltages. The morphing structure’s capabilities are measured through experimental testing and the predictions of the analytical model are compared to the results. We demonstrate shape morphing by deforming the structure with an actuator, increasing the effective structural modulus and then removing the actuation force. Our tests show a fixed shape change in the structure of up to 20% of the total deformation. Feasibility is also discussed for real-world applications and suggested areas for further exploration on the topic are presented.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
17 June 2016 |
| Date Type: |
Publication |
| Defense Date: |
20 April 2015 |
| Approval Date: |
17 June 2016 |
| Submission Date: |
28 May 2015 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Number of Pages: |
99 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Structural shape morphing, variable modulus structures, smart materials and structures, electroactive polymer materials and Ionomers |
| Date Deposited: |
17 Jun 2016 19:11 |
| Last Modified: |
17 Jun 2021 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/25288 |
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