0
TECHNICAL PAPERS

# Characterization and Variational Modeling of Ionic Polymer Transducers

[+] Author and Article Information
Miles A. Buechler1

WT-2 Analysis and Prediction, Weapons Engineering Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545buechler@lanl.gov

Donald J. Leo

Center for Intelligent Materials Systems and Structures, Department of Mechanical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061donleo@vt.edu

1

Corresponding author.

J. Vib. Acoust 129(1), 113-120 (Oct 17, 2006) (8 pages) doi:10.1115/1.2424973 History: Received August 04, 2005; Revised October 17, 2006

## Abstract

Ionomeric polymers are a promising class of intelligent material which exhibit electromechanical coupling similar to that of piezoelectric bimorphs. Ionomeric polymers are much more compliant than piezoelectric ceramics or polymers and have been shown to produce actuation strain on the order of 2% at operating voltages between $1V$ and $3V$ (Akle, 2004, Proceedings IMECE). Their high compliance is advantageous in low force sensing configurations because ionic polymers have a very little impact on the dynamics of the measured system. Here we present a variational approach to the dynamic modeling of structures which incorporate ionic polymer materials. To demonstrate the method a cantilever beam model is developed using this variational approach. The modeling approach requires a priori knowledge of three empirically determined material properties: elastic modulus, dielectric permittivity, and effective strain coefficient. Previous work by Newbury and Leo has demonstrated that these three parameters are strongly frequency dependent in the range between less than $1Hz$ to frequencies greater than $1kHz$. Combining the frequency-dependent material parameters with the variational method produces a second-order matrix representation of the structure. The frequency dependence of the material parameters is incorporated using a complex-property approach similar to the techniques for modeling viscoelastic materials. A transducer is manufactured and the method of material characterization is applied to determine the mtaerial properties. Additional experiments are performed on this transducer and both the material and structural model are validated. Finally, the model is shown to predict sensing response very well in comparison to experimental results, which supports the use of an energy-based variational approach for modeling ionomeric polymer transducers.

<>

## Figures

Figure 1

Transducer geometry (5)

Figure 2

Free deflection test setup

Figure 3

Stiffness sensing test setup

Figure 4

Mechanical stiffness measurements and curve fit

Figure 5

Electrical impedance measurements

Figure 6

Free deflection at the actuator tip

Figure 7

Complex material parameters 0.1–500Hz

Figure 8

Free deflection at three points along the actuator

Figure 9

Comparison of deflections to structural mode shapes

Figure 10

Comparison experimental sensing response to the model

## Discussions

Some tools below are only available to our subscribers or users with an online account.

### Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections