In this work a method is presented to predict the performance of dynamically actuated DE roll-actuators depending on both, material and design parameters. Dielectric elastomer (DEs) have very suitable properties, such as very fast response times, high electric energy density, high stretchability and inexpensive raw materials. They can be utilized as wideband dynamic actuators, for example loud speakers and shakers. Such dynamic dielectric elastomer actuators (DEAs) have a very high degree of functional integration, no permanent magnetic fields, are lightweight and long-term stable, which qualifies them for unique applications.

The large variety of usable dielectric elastomers in combination with a multitude of possible actuator configurations, e. g. roll-actuators, and their large number of constructional degrees of freedom necessitates an efficient method to predict the actuators behaviors to meet the application requirements. A suitable method to solve this design problem is the combination of Finite-Element and network methods. To obtain the network parameters for specific mechanical and or electrical bias configurations, preliminary considerations have to be performed.

Due to the multiple nonlinearities of DEs, such as electrostriction, transverse deformation and hyperelasticity, the geometrical parameters at the operating point have to be determined iteratively. For geometrically complex configurations practically FEM is applied, which can handle multifield problems (electrostatic, mechanical, hyperelastics) and high aspect ratios. From the geometrical parameters and preload conditions the network parameters are computed analog to conventional electrostatic transducers. The network simulation predicts the dynamic behavior in the time and frequency domain. The simulation model can be easily extended to consider various boundary conditions and changing loads, e. g. mass and stiffness. Because network simulations are very time efficient, they allow for extensive parameter studies. In addition, by applying filter theory a suitable set of load conditions can be determined in order to optimize the desired output performance.

DE roll-actuators in push configuration exhibit a distinct modal behavior in axial direction depending on the boundary conditions at actuators end terminals. This was met by incorporating a longitudinal waveguide network model. With this method DE roll-actuators in push configuration were designed and manufactured. Experimental studies confirm the made predictions. The gained understanding of the interaction of construction, boundary conditions and load on the performance and especially the specific location of resonances and anti-resonances supports the development of tailor-made actuators.


Prediction of the Behavior of Dynamically Actuated DE Roll-Actuators Using Equivalent Circuits

Division / Sponsors: 
Aerospace Division

Paper Proceedings: https://asmedigitalcollection.asme.org/SMASIS/SMASIS2020/volume/84027

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