Influence of electric field, temperature, humidity, elastomer material, and encapsulation on the lifetime of dielectric elastomer actuators (DEAs) under DC actuation

Dielectric elastomer actuators with enhanced flexibility were prepared by thermosetting polyurethane (TSU) consisting of polypropylene glycol (PPG) as an active hydrogen component and toluene diisocyanate (TDI) as an isocyanate component. The improvement was achieved by less hard segment content, i.e. less isocyanate index, the synthesized film actuators were compared with the actuator softened using a plasticizer. It was found that the film actuators prepared by this method had significant advantages in actuation under a lower electric field as well as the increase of electrical breakdown strength and of strain. Furthermore, the mechanically-stretched effect of the films was also evaluated. It turned out that prestrain up to 200% was effective in the increase of electrical breakdown strength while maintaining the actuation under a lower electric field. However, prestrain over 200% caused a decrease in actuation under a lower electric field.

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Effect of humidity, temperature, and elastomer material on the lifetime of silicone-based dielectric elastomer actuators under a constant DC electric field (Conference Presentation)

Electroactive Polymer Actuators and Devices (EAPAD) XXII ◽

10.1117/12.2558428 ◽

2020 ◽

Author(s):

Fabio Beco Albuquerque ◽

Herbert R. Shea

Keyword(s):

Electric Field ◽

Dielectric Elastomer ◽

Dielectric Elastomer Actuators ◽

Dc Electric Field

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An Energy-Based Approach to Extract the Dynamic Instability Parameters of Dielectric Elastomer Actuators

Journal of Applied Mechanics ◽

10.1115/1.4027925 ◽

2014 ◽

Vol 81 (9) ◽

Cited By ~ 17

Author(s):

M. M. Joglekar

Keyword(s):

Electric Field ◽

Dynamic Instability ◽

Time History ◽

Material Model ◽

Dielectric Elastomer ◽

Step Voltage ◽

Dielectric Elastomer Actuators ◽

Time History Response ◽

Maximum Stretch ◽

Static Instability

An energy-based approach is presented to extract the thresholds on the transient dynamic response of step voltage driven dielectric elastomer actuators (DEAs). The proposed approach relies on establishing the energy balance at the point of maximum stretch in an oscillation cycle followed by the application of an instability condition to extract the dynamic instability parameters. Explicit expressions are developed for the critical values of maximum stretch and the corresponding nominal electric field, thus circumventing the need to perform iterative time-integrations of the equation of motion. The underlying principles of the approach are enunciated for the neo-Hookean material model and further extended to analyze relatively complex multiparameter hyperelastic models (Mooney–Rivlin and Ogden) that are employed prevalently for investigating the behavior of DEAs. The dynamic instability parameters predicted using the energy method are validated by examining the time-history response of the actuator in the vicinity of the dynamic instability. The development of dynamic instability parameters is complemented by energy-based extraction of static instability parameters to facilitate a quick comparison between the two. It is inferred quantitatively that the nominal electric field sufficient to cause the dynamic instability and the corresponding thickness stretch is lower than those corresponding to the static instability. A set of representative case studies for multiparameter material models is presented at the end, which can be used as an input for further experimental corroboration. The results of the present investigation can find their potential use in the design of DEAs subjected to transient loading.

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