Modeling of Electromechanical Transduction in Ionic Polymer Materials

2002 ◽  
Author(s):  
Kenneth Newbury ◽  
Donald J. Leo
Keyword(s):  
Electromechanical Coupling ◽  
Low Voltage ◽  
Linear Equations ◽  
Polymer Materials ◽  
System Level ◽  
Model Parameters ◽  
Symmetric Model ◽  
Sample Length ◽  
Ionic Polymer ◽  
Electromechanical Transduction

A coupled, linear electromechanical model is developed for ionic polymer transducers. The model is based on the linear equations for a piezoelectric material. Integrating the equations over the geometry of the transducer produces a model of the electromechanical coupling of the polymer transducers as a function of fundamental material parameters and geometry. Explicit modeling of electromechanical coupling produces a model that is useful for analyzing sensing or actuation using ionic polymer transducers. Experiments on polymer samples verify the scaling of the model parameters as a function of sample length and width. The results also demonstrate the reciprocity of the electromechanical coupling. The symmetric model is expressed as a linear transformer which can be incorporated into system-level models for design of devices that utilize ionic polymer materials. The model is limited to linear operation at low-voltage with constant levels of material hydration.

Investigation of Extensional Actuation Strain in Ionomeric Polymer Transducers

Aerospace ◽  
2005 ◽  
Author(s):  
Barbar J. Akle ◽  
Donald J. Leo
Keyword(s):  
Electromechanical Coupling ◽  
Active Material ◽  
Bending Moment ◽  
Sine Wave ◽  
Polymer Materials ◽  
Quadratic Term ◽  
Beam Shape ◽  
Ionic Polymer ◽  
Assembly Method ◽  
Direct Assembly

Ionomeric polymer transducers have received considerable attention in the past ten years due to their ability to generate large bending strain and moderate stress at low applied voltages. Bending transducers made of an ionomeric polymer membrane sandwiched between two flexible electrodes deform through the expansion of one electrode and contraction of the opposite electrode due to cation displacement. This is similar to a bimorph type actuation. In this study we report actuation through the thickness of the membrane, leading to the potential of a new actuation mechanism for ionomeric polymer materials. Several experiments are performed to compare the bending actuation with the extensional actuation capability. The direct assembly method previously developed by the authors is used to fabricate ionic polymer transducers with controlled electrode dimensions and morphology. Electrodes with varying thickness are used to alter thickness of the active material. In the first experiment, the actuators are cut in beam shape and are allowed to bend in cantilever configuration. In the second configuration, bending is constrained by sandwiching the membranes between two solid metal plates and force is measured across the thickness of the actuator. A bimorph model is used to assess the effect of electrode thickness on the strain. An electromechanical coupling model presented by Leo et al. [1] determined the strain in the active areas as a function of the charge. This model is presented with a linear and a quadratic term that produces a 1st harmonic response for a sine wave actuation input. The quadratic term in the strain generates a zero net bending moment for ionic polymer transducers with symmetric electrodes. The linear term is also canceled in extensional actuation for symmetric electrodes. Experimental results demonstrates strain on the order of 110 μstrain in the thickness direction compared to 1700 μstrain peak to peak on the external fibers for the same transducer when it is allowed to bend under +/−2V potential at 0.5 Hz.

Characterization and Variational Modeling of Ionic Polymer Transducers

2006 ◽  
Vol 129 (1) ◽  
pp. 113-120 ◽  
Author(s):  
Miles A. Buechler ◽  
Donald J. Leo
Keyword(s):  
Variational Approach ◽  
Electromechanical Coupling ◽  
Structural Model ◽  
A Priori ◽  
Effective Strain ◽  
Polymer Materials ◽  
Beam Model ◽  
Frequency Dependent ◽  
Ionic Polymer ◽  
Material Parameters

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 et al., 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.

Mechanical Work and Electromechanical Coupling in Ionic Polymer Bender Actuators

2001 ◽  
Author(s):  
Kenneth Newbury ◽  
Donald J. Leo ◽  
Orion Parrot
Keyword(s):  
Parameter Identification ◽  
Electromechanical Coupling ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Mechanical Work ◽  
Model Parameters ◽  
Ionic Polymer ◽  
Step Input ◽  
Electromechanical Model ◽  
Input Range

Abstract This paper presents a coupled, electromechanical model of a Nafion-based ionic polymer transducer used in the cantilevered bender configuration. A comparison of simulated and experimental responses for a 0.2mm × 5.0mm × 17mm actuator validates both the form of the model and the empirically determined model parameters. In one of the experiments used for parameter identification, the short circuit current is found to be proportional to the induced actuator velocity, with the constant of proportionality equal to 7.5E−04 A m / s . This model differs from those presented by other researchers in that it is simple, dynamic, and is able to represent the transducer as either a sensor or as an actuator. Also presented is an assessment of the polymer actuators’ ability to perform mechanical work. The results of a series of force versus deflection experiments are outlined, and energy densities are calculated to facilitate comparison with other actuator technologies. The maximum blocked force with a 1.25V step input was 1.6mN (with a 17mm actuator), and the maximum free deflection with a 1.25V step input was 1.8mm (with a 22mm actuator). The energy densities ranged from 1.1 to 12.8 mJ/kg and 3.4E−06 to 4.0E−05 mJ/mm3 with an input range of 0.75V to 1.25V.

scholarly journals Modeling of German Low Voltage Cables with Ground Return Path

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265 ◽  
Author(s):  
Johanna Geis-Schroer ◽  
Sebastian Hubschneider ◽  
Lukas Held ◽  
Frederik Gielnik ◽  
Michael Armbruster ◽  
...  
Keyword(s):  
Low Voltage ◽  
Measurement Data ◽  
Analytical Calculation ◽  
Laboratory Measurement ◽  
Model Parameters ◽  
Calculation Methods ◽  
Modeling Approach ◽  
Measurement Results ◽  
Simulation Results ◽  
Return Path

In this contribution, measurement data of phase, neutral, and ground currents from real low voltage (LV) feeders in Germany is presented and analyzed. The data obtained is used to review and evaluate common modeling approaches for LV systems. An alternative modeling approach for detailed cable and ground modeling, which allows for the consideration of typical German LV earthing conditions and asymmetrical cable design, is proposed. Further, analytical calculation methods for model parameters are described and compared to laboratory measurement results of real LV cables. The models are then evaluated in terms of parameter sensitivity and parameter relevance, focusing on the influence of conventionally performed simplifications, such as neglecting house junction cables, shunt admittances, or temperature dependencies. By comparing measurement data from a real LV feeder to simulation results, the proposed modeling approach is validated.

Biomimetic Applications of Ionic Polymer Metal Composites (IPMC) Actuators - A Critical Review

2014 ◽  
Vol 20 ◽  
pp. 1-10 ◽  
Author(s):  
Muhammad Farid ◽  
Zhao Gang ◽  
Tran Linh Khuong ◽  
Zhuang Zhi Sun ◽  
Naveed Ur Rehman ◽  
...  
Keyword(s):  
Critical Review ◽  
Low Voltage ◽  
Metal Composite ◽  
Ionic Polymer Metal Composite ◽  
Metal Composites ◽  
Ionic Polymer Metal Composites ◽  
Ionic Polymer ◽  
Design And Manufacturing ◽  
Polymer Metal ◽  
Biomedical Field

Biomimetic is the field of engineering in which biological creatures and their functions are investigated and are used as the basis for the design and manufacturing of machines. Ionic Polymer Metal Composite (IPMC) is a smart material which has demonstrated a meaningful bending and tip force after the application of a low voltage. It is light-weighted, flexible, easily actuated, multi-directional applicable and requires simple manufacturing. Resultantly, IPMC has attracted scientists and researchers to analyze it further and consider it for any industrial and biomimetic applications. Presently, the research on IPMC is bi-directional oriented. A few groups of researchers are busy to find out the causes for the weaknesses of the material and to find out any remedy for them. The second class of scientists is exploring new areas of applications where IPMC material can be used. Although, the application zone of IPMC is ranging from micropumps diaphragms to surgical holding devices, this paper provides an overview of the IPMC application in biomimetic and biomedical field.

Fabrication of Ionic Polymer Metal Composite Actuator with Palladium Electrodes and Evaluation of its Bending Response

2009 ◽  
Vol 1190 ◽  
Author(s):  
Takuma Kobayashi ◽  
Takeshi Kuribayashi ◽  
Masaki Omiya
Keyword(s):  
Electric Field ◽  
Sample Length ◽  
Metal Composite ◽  
Ionic Polymer Metal Composite ◽  
Ionic Polymer ◽  
Palladium Electrode ◽  
Wide Range ◽  
Polymer Metal ◽  
Bending Response ◽  
Tip Displacement

AbstractWe built up the way of fabricating IPMC actuator with palladium electrodes and we found that it showed large bending response than Au-plated IPMC actuator. An ionic polymer-metal composite (IPMC) consisting of a thin perfuorinated ionomer membrane, electrodes plated on both faces, undergoes large bending motion when a small electric field is applied across its thickness in a hydrated state. The characteristics of IPMC are ease of miniaturization, low density, and mechanical flexibility. Therefore, it is considered to have a wide range of applications from MEMS sensor to artificial muscle. However, there are problems on IPMC. First, its mechanical and electric characteristics have not been clarified because of the complex mechanism of the deformation. Second, it is high-priced because most of IPMC actuators use gold or platinum as electrodes. In order for IPMC actuator to be widely put to practical use, we should solve these problems. Hence, this research focuses on fabrication of IPMC actuator with palladium electrode, which is cheaper than gold or platinum, and evaluation of its mechanical properties such as its tip displacement. We fabricated IPMC consisting of a thin Nafion® membrane, which is the film with fluorocarbon back-bones and mobile cations, sandwiched between two thin palladium plates. The surface resistivity was 2.88±0.18Ω/sq., so it could be said to be enough small. Then, we observed its cross section by using FE-SEM. As a result, palladium plates were evenly coated and its thickness was about 30μm. Also, we carried out an actuation test for two kinds of IPMCs: one was fabricated by using Nafion®117 (thickness 183μm), the other was by Nafion®115 (thickness 127μm). In this test, the relationship between voltage (0˜4V) across its thickness and tip displacement for the cantilevered strip of the IPMC was measured. Then we found that IPMCs showed large bending motion under a low electric field. When Nafion®117 sample was subjected to voltage of 1.5V, the ratio of the tip displacement to the sample length was 0.35, which was lager bending than Au-plated IPMC actuator, whose ratio of the tip displacement to the sample length was 0.12 [1]. When Nafion®115 sample was applied to 1.5V, the ratio of the tip displacement to the sample length was 0.22. Then, we found that Nafion®117 bended in a larger way than Nafion®115. Reference [1]Sia Nemat-Nesser and Yongxian Wu,”Comparative experimental study of ionic polymer-metal composites with different backbone ionomers and in various cation forms”, Journal of Applied Physics,93,5255 (2003)

Hybrid Actuation in Coupled Ionic / Conducting Polymer Devices

2003 ◽  
Vol 785 ◽  
Author(s):  
Matthew D. Bennett ◽  
Donald J. Leo
Keyword(s):  
Conducting Polymer ◽  
Smart Materials ◽  
Electromechanical Coupling ◽  
Performance Metrics ◽  
Polymer Membrane ◽  
Low Frequencies ◽  
Ionic Polymer ◽  
Polymer Actuators ◽  
Ionic Conducting ◽  
Initial Results

ABSTRACTIonic polymer membrane actuators represent a relatively new and exciting entry into the field of smart materials. Several key limitations of these transducers have prevented them from experiencing widespread use, however. For example, the bandwidth of these devices is limited at very low frequencies by characteristic relaxation and at high frequencies by the low elastic modulus of the polymer. In this paper, an overview of the initial results of work with hybrid ionic / conducting polymer actuators is presented. These hybrid actuators are devices that combine the electromechanical coupling of ionic polymer actuators and conducting polymer actuators into one coupled device. Initial results show that these hybrid devices have the potential to offer marked advantages over traditional ionic polymer membrane transducers, including increased stress and strain generation and higher actuation bandwidth. Details of the preparation of these devices and performance metrics are presented and comparisons to baseline materials are made.

Constraint Management Methodology for Conceptual Design Tradeoff Studies

1996 ◽  
Author(s):  
Sudhakar Y. Reddy ◽  
Kenneth W. Fertig ◽  
David E. Smith
Keyword(s):  
Conceptual Design ◽  
Imaging System ◽  
Linear Equations ◽  
Performance Model ◽  
System Level ◽  
Cost Models ◽  
Practical Applications ◽  
Constraint Management ◽  
Computational Procedures ◽  
Thermal Imaging System

Abstract This paper presents a constraint management methodology, which facilitates tradeoff studies during conceptual design. This approach represents design models as constraints between variables, and uses the resulting constraint network to automatically derive computational procedures for performing user-specified tradeoff studies. By decomposing large constraint networks into smaller pieces that can be solved robustly, this approach can solve extremely large systems of non-linear equations present in practical system models. Design Sheet is a software implementation of this methodology; it allows the designer to interactively develop models, flexibly define tradeoff studies, and quickly explore large areas of design space to study how the different performance and cost criteria tradeoff with respect to one another. Design Sheet has been used on practical applications ranging from the system-level design of spacecraft using combined performance and cost models to the preliminary design of automotive bearings. This paper demonstrates the unique capabilities of Design Sheet in performing design tradeoff studies, using a thermal imaging system performance model developed for the DARPA MADE program.

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