scholarly journals Humidity Effect on Dynamic Electromechanical Properties of Polyacrylic Dielectric Elastomer: An Experimental Study

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 784
Author(s):  
Yuchen Zuo ◽  
Yuxi Ding ◽  
Junshi Zhang ◽  
Mingliang Zhu ◽  
Lei Liu ◽  
...  

In this research, by utilizing the Very-High-Bond (VHB) 4905 elastomer, we carry out an experimental examination on the humidity effect on dynamic electromechanical performances of dielectric elastomers, including the dynamic response and viscoelastic creeping. Firstly, we experimentally analyze effects of the pre-stretch, peak voltage, waveform and frequency of the dynamic response of VHB 4905 elastomer under several ambient humidities. In general, the amplitude of dynamic deformation gradually adds up with the increasing humidity. Besides, it is found that the amplitude affected by different parameters shows diverse sensitivity to humidity. Subsequently, effect of humidity on the viscoelastic creeping of VHB 4905 is explored. The results demonstrate that, subject to different ambient humidities, the viscoelastic creeping under Alternating Current (AC) voltage is similar to that under Direct Current (DC) voltage. Furthermore, the equilibrium position of dynamic viscoelastic creep enlarges gradually with the humidity, regardless of voltage waveforms. For the dielectric elastomer with a pre-stretch ratio of 3, when the humidity increases from 20% to 80%, the increase of average equilibrium position of dynamic viscoelastic creep is larger than 1599%.

2021 ◽  
Vol 193 ◽  
pp. 106177
Author(s):  
Junshi Zhang ◽  
Liling Tang ◽  
Lei Liu ◽  
Jianwen Zhao ◽  
Zhichun Yang ◽  
...  

Author(s):  
Hao Dong ◽  
Lin Du ◽  
Rongchun Hu ◽  
Shuo Zhang ◽  
Zichen Deng

Abstract Dielectric elastomers are widely used in many fields due to their advantages of high deformability, light weight, biological compatibility, and high efficiency. In this study, the stochastic dynamic response and bifurcation of a dielectric elastomer balloon (DEB) with viscoelasticity are investigated. Firstly, the rheological model is adopted to describe the viscoelasticity of the DEB, and the dynamic model is deduced by using the free energy method. The effect of viscoelasticity on the state of equilibrium with static pressure and voltage is analysed. Then, the stochastic differential equation about the perturbation around the state of equilibrium is derived when the DEB is under random pressure and static voltage. The steady-state probability densities of the perturbation stretch ratio are determined by the generalized cell mapping method. The effects of parameter conditions on the mean value of the perturbation stretch ratio are calculated. Finally, sinusoidal voltage and random pressure are applied to the viscoelastic DEB, and the phenomenon of P-bifurcation is observed. Our results are compared with those obtained from Monte Carlo simulation to verify their accuracy. This work provides a potential theoretical reference for the design and application of DEs.


RSC Advances ◽  
2017 ◽  
Vol 7 (59) ◽  
pp. 37148-37157 ◽  
Author(s):  
Mengnan Ruan ◽  
Dan Yang ◽  
Wenli Guo ◽  
Shuo Huang ◽  
Yibo Wu ◽  
...  

Barium titanate (BT) particles, BT-KH570 particles, and polar plasticizer tri-n-butyl phosphate (TBP) were added into BIIR matrix to form a dielectric elastomer composite, which had a high dielectric constant, good mechanical properties, and large actuated strain.


Author(s):  
N. Nurminen ◽  
A. Ellman ◽  
V. Jouppila ◽  
M. Paajanen ◽  
M. Karesoja

The electromechanical properties of elastomer material change when different levels of stretching are applied to the elastomer film. The generated stress and expansion of the EAP material depend on the electric field across the material and its relative permeability. Some of the best known commercial dielectric elastomer materials are based on acrylic elastomers, e.g. 3M VHB 4910 or 4905 adhesive tape. In this work, the VHB 4910 tape was used as a reference material for different types of acrylic nanoclay compound materials. These new type of nanoclay elastomer compounds were tested because the addition of clay into the elastomer was assumed to increase its actuating performance. Different voltage and pre-stretching levels were used in the measurements. Current-voltage characteristics and isometric stress measurements were used to study the energy efficiency, frequency dependent behavior, reactivity and isometric stress performance of the EAP materials. Based on the electromechanical characterization and material properties, a general hyperelastic material model was developed. According to the preliminary tests, the nanoclay compound seems to be a bit stiffer than VHB 4910 resulting in a greater isometric stress response.


Aerospace ◽  
2005 ◽  
Author(s):  
Nakhiah Goulbourne ◽  
Eric Mockensturm ◽  
Mary Frecker

This paper presents dynamic results for spherical dielectric elastomer actuators subject to an inflating mechanical pressure and an applied voltage. Different equilibria modes arise during dynamic operation due to inertial effects. In previous work, the inertial effects have been studied for the limited case of a constant applied pressure during membrane deformation [1]. Here, novel results are presented in which the dynamic response of spherical dielectric elastomer actuators to a pressure-time loading history as well as a more realistic constant gas flow rate are considered. The results are calculated for both the damped and the zero-damped cases. The spherical membrane is assumed to follow the Mooney material model where various inflation modes arise depending on the material parameters. The range of Mooney material parameters considered, the driving pressure and the applied voltage all affect the dynamic response.


2018 ◽  
Vol 29 (11) ◽  
pp. 2424-2436 ◽  
Author(s):  
Yanping Tian ◽  
Yong Wang ◽  
Xiaoling Jin ◽  
Zhilong Huang

Dielectric elastomer actuators have gained extensive attention in scientific and industrial communities with the rapid development of soft robot technology. There still remain some questions on the control aspect of nonlinear system with dielectric elastomer actuator. The first is whether the soft actuator can successfully drive the primary structure to track an arbitrary prescribed trajectory. The second is how to suppress the random vibration around the equilibrium position when the primary structure is disturbed by external excitation. This article seeks the answers for these two questions. By directly solving the governing equation of motion, an open-loop control technique is designed to track a prescribed trajectory. The effectiveness of the trajectory tracking technique is investigated and the limitation is illustrated by the influence of inertia of the primary structure. Based on the stochastic averaging of energy envelope and stochastic dynamic programming principle, a clipped control strategy is proposed by slightly adjusting the voltage in real time to suppress the random vibration around the equilibrium position. The good effectiveness and high robustness of the clipped control strategy are verified numerically. This work may provide some guidelines for the control aspect of nonlinear systems with dielectric elastomer actuators.


Author(s):  
Robert L. Lowe ◽  
Christopher G. Cooley

Abstract This paper investigates the nonlinear dynamics of square dielectric elastomer membranes under time-dependent, through-thickness compressive loading. The dielectric elastomer is modeled as an isotropic ideal dielectric, with mechanical stiffening at large strains captured using the Gent hyperelastic constitutive model. The equation of motion for the in-plane membrane stretch is derived using Hamilton’s principle. The static response of the membrane is first investigated, with equilibrium stretches calculated numerically for a wide range of compressive pre-loads and applied voltages. Snap-through instabilities are observed, with the critical snap-through voltage decreasing with increasing compressive pre-load. The dynamic response of the membrane is then investigated under forced harmonic excitation. Frequency response plots characterizing the steady-state vibration reveal primary, subharmonic, and superharmonic resonances. Near these resonances, two stable vibration states are possible, corresponding to upper and lower branches in the frequency response. Significant and practically meaningful differences in the dynamic response are observed when the system vibrates at a fixed frequency about the upper and lower branches, a feature not discussed in previous research.


2010 ◽  
Vol 519 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Bori Kim ◽  
Kyongho Min ◽  
Jungahn Kim ◽  
Soon Man Hong ◽  
Chong Min Koo

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