1. Dielectric Elastomers
AE 510: Research Project Presentation
By: Carl Johnson
October 22, 2002

2. How Dielectric Elastomers Work
Dielectric Elastomers have a polymer (aka plastic) film between two electrodes
When an electric field is induced between the electrodes the electrostatic forces cause a change in shape (see figure)
Ref. 1

3. Governing Equation of Dielectric Elastomers
p=e*e0*E2
Where:
p is effective compressive stress
e is relative dielectric constant
e0 is permittivity of free space (a constant)
E is strength of electric field between diodes

4. Advantages of Dielectric Elastomers
Similar materials include:
Shape memory alloys (SMA)
Piezoelectrics
Compared to these dielectric elastomers have:
Higher energy density
Lower weight
Higher efficiencies
Higher maximum strains

5. Dielectric Elastomer Comparison Chart
Shape Memory Alloys
Piezoelectrics
Dielectric Elastomers
Note Similarity of Dielectric Elastomers and Natural Muscle

6. Applications: Actuators
Dielectric elastomers are well suited to actuators
Their similarity to natural muscle makes them ideal for use on robots (see right)
They could also be used to motivate insect-like micro UAVs
Dielectric elastomers could be used for human prostheses and make the six million dollar man a reality (see title slide)

7. Applications: Heel-Strike Generator
DoD is using dielectric elastomers to develop a heel-strike generator to go in soldiers boots that would generate electricity just from walking
A dielectric elastomer generator works like an actuator in reverse (mechanical-to-electrical instead of electrical-to-mechanical energy)

8. References:
Pelrine, Ron et al. “High Strain Actuator Materials Based on Dielectric Elastomers.” SRI International
Wingert, Andrew et al. “Hyper-Redundant Robot Manipulators Actuated by Optimized Binary Dielectric Elastomers.” Smart Structures and Materials Symposium 2002.
SRI International Comparison Tables/Charts
Bar-Cohen, Yoseph. “Electroactive Polymers as Artificial Muscles – Capabilities, Potentials and Challenges.” Robotics 2000 and Space Albuquerque, NM
Pelrine, Ron. And Kornbluh, Roy. “Recent Progress in Heel-strike Generators using Electroactive Polymers.”
Zorpette, Glenn. “Fly on the Wall.” Red Herring Magazine. October 2000.