First steps in modeling thermal actuation of twisted polymer actuators using virgin material properties

Michael W. Shafer, Heidi P Feigenbaum, Daniel Pugh, Matthew Fisher

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)

Abstract

Artificial muscle systems have the potential to impact many technologies ranging from advanced prosthesis to miniature robotics. Recently, it has been shown that twisting drawn polymer fibers such as nylon can result in torsional or tensile actuators depending on the final fiber configuration. The actuation phenomenon relies on the anisotropic nature of the fibers moduli and thermal expansion. They have high axial stiffness, low shear stiffness, and expand more radially when heated than axially. If a polymer fiber is twisted but not coiled, these characteristics result in a torsional actuator that will untwist when heated. During the fabrication process, these twisted polymers can be configured helically before annealing. In this configuration, the untwisting that occurs in a straight twisted fiber results in a contraction or extension depending on relative directions of twist and coiling. In these ways, these materials can be used to create both torsional or axial actuators with extremely high specific work capabilities. To date, the focus of research on twisted polymer actuators (TPAs) and twisted-coiled polymer actuators (TCPAs) has been actuator characterization that demonstrates the technologies capabilities. Our work focuses here on applying a 2D analysis of individual layers of the TPAs to predict thermally induced twisting angle and fiber length based on virgin (untwisted) material properties and actuator parameters like fiber length and inserted twist. A multi-axis rheometer with a controlled thermal environmental chamber was used to twist, anneal, and test thermally induced actuation. Experimentally measured angle of untwist and axial contraction after heating are compare the the model. In comparing the experimental results with the two dimensional model, it appears that the difference between the 2D model and experimental results can be explained by the longitudinal stresses that develop inside the material. Future work will aim to include these effects in the model in order to be able to use this model in the design of TPAs.

Original languageEnglish (US)
Title of host publicationModeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting
PublisherAmerican Society of Mechanical Engineers
Volume2
ISBN (Electronic)9780791850497
DOIs
StatePublished - 2016
EventASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2016 - Stowe, United States
Duration: Sep 28 2016Sep 30 2016

Other

OtherASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2016
CountryUnited States
CityStowe
Period9/28/169/30/16

Fingerprint

Materials properties
Actuators
Polymers
Fibers
Stiffness
Environmental chambers
Hot Temperature
Rheometers
Thermal expansion
Muscle
Robotics
Annealing
Heating
Fabrication

ASJC Scopus subject areas

  • Building and Construction
  • Civil and Structural Engineering
  • Control and Systems Engineering
  • Mechanics of Materials

Cite this

Shafer, M. W., Feigenbaum, H. P., Pugh, D., & Fisher, M. (2016). First steps in modeling thermal actuation of twisted polymer actuators using virgin material properties. In Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting (Vol. 2). [V002T06A017] American Society of Mechanical Engineers. https://doi.org/10.1115/SMASIS2016-9292

First steps in modeling thermal actuation of twisted polymer actuators using virgin material properties. / Shafer, Michael W.; Feigenbaum, Heidi P; Pugh, Daniel; Fisher, Matthew.

Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting. Vol. 2 American Society of Mechanical Engineers, 2016. V002T06A017.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Shafer, MW, Feigenbaum, HP, Pugh, D & Fisher, M 2016, First steps in modeling thermal actuation of twisted polymer actuators using virgin material properties. in Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting. vol. 2, V002T06A017, American Society of Mechanical Engineers, ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems, SMASIS 2016, Stowe, United States, 9/28/16. https://doi.org/10.1115/SMASIS2016-9292
Shafer MW, Feigenbaum HP, Pugh D, Fisher M. First steps in modeling thermal actuation of twisted polymer actuators using virgin material properties. In Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting. Vol. 2. American Society of Mechanical Engineers. 2016. V002T06A017 https://doi.org/10.1115/SMASIS2016-9292
Shafer, Michael W. ; Feigenbaum, Heidi P ; Pugh, Daniel ; Fisher, Matthew. / First steps in modeling thermal actuation of twisted polymer actuators using virgin material properties. Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting. Vol. 2 American Society of Mechanical Engineers, 2016.
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