A novel active material for controllable, high work density applications was
designed, fabricated, analyzed, and tested. This active material uses a lens-shaped
element to implement simple shear motion with gas pressure actuation. The lens element
is a bladder-filled Kevlar fabric embedded in a polyurethane matrix.
The polyurethane’s hyperelastic material parameters were found by experiment
and estimated by numerical analysis. The Ogden material constant set found shows good
agreement within the shear actuator’s working range.
A fabricated, single-element shear actuator reached 34.2% free shear strain when
pressurized to 1.03 MPa. A unitary shear actuator was modeled as were single-acting
and dual-acting shear actuator arrays so that solitary and multi-cell behaviors were
estimated. Actuator work performance and power from nonlinear finite element analysis
found conventional work density is 0.2289 MJ/m3 and 0.2482 MJ/m3, for the singleacting
and double-acting shear actuator, respectively. Scientific work densities are 0.0758 MJ/m3 and 0.0375 MJ/m3, for single-acting and double-acting shear actuators,
respectively. Calculation shows the volumetric power for a single-acting shear actuator
is 0.4578 MW/m3 and 0.4964 MW/m3 for the double-acting shear actuator.
Finally, a nastic actuator is applied to twist a generic structural beam. The nasticmaterial
actuated structure has an advantage over conventional actuator systems. Work
per unit volume for nastic materials is 2280~8471% higher than conventional, discrete
actuators that use electric motors. When compared by work per unit mass, this nastic
actuator is 2592~13900% better than conventional actuator because nastic actuator is
made from lighter materials and it distributes the actuation throughout the structure,
which eliminates connecting components.
The nastic actuator’s volumetric power is 2217~8602% higher than conventional
actuators. Finally, the nastic actuator is 2656~14269% higher than conventional
actuators for power per unit mass.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2349 |
| Date | 15 May 2009 |
| Creators | Lee, Sang Jin |
| Contributors | Creasy, Terry S. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
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