dielectric elastomer

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For my new junior research group "MEiTNER - Multifunctional dielectric elastomer electronics for next generation soft robotics", I am searching for two PhD candidates at TU Dresden. The possitions come with full salary and all German social security. 

Soft wall-climbing robots

Guoying Gu, Jiang Zou, Ruike Zhao, Xuanhe Zhao and Xiangyang Zhu

Science Robotics, 2018, Vol. 3, Issue 25, eaat2874

Self-healing materials can repair damage caused by mechanical wear, thereby extending lifetime of devices. Here, a transparent, self-healing, highly stretchable ionic conductor is presented that autonomously heals after experiencing severe mechanical damage.

P. I. Galich and S. Rudykh, Manipulating pressure and shear waves in dielectric elastomers via external electric stimuli. International Journal of Solids and Structures, 91, 18 – 25 (2016)

B. Tavakol and D.P. Holmes, Appl. Phys. Lett., 108, 112901, (2016).

This paper explores the critical and post-bulging bifurcation of a cylindrical dielectric elastomer (DE) tube undergoing finite deformation under electro-mechanical coupling loading. Explicit expressions for the critical conditions of electro-mechanical bifurcation are derived by using a simplified mathematical method. The post-bifurcation path is comprehensively investigated by specifying the material model as ideal dielectric elastomer.

Under the actions of internal pressure and electric voltage, a spherical dielectric elastomer balloon usually keeps a sphere during its deformation, which has also been assumed in many previous studies. In this article, using linear perturbation analysis, we demonstrate that a spherical dielectric elastomer balloon may bifurcate to a nonspherical shape under certain electromechanical loading conditions.

Cephalopod-inspired Design of Electro-mechano-chemically Responsive Elastomers for On-demand Fluorescent Patterning

Qiming Wang, Gregory R. Gossweiler, Stephen L. Craig*, Xuanhe Zhao*

A highly deformable capacitor made of a soft dielectric and two conformal

electrodes can switch between two states discontinuously, by a first-order transition, as the total

charge varies gradually. When the total charge is small, it spreads evenly over the area of the

capacitor, and the capacitor deforms homogeneously. When the total charge is large, it localizes in

a small region of the capacitor, and this region thins down preferentially. The capacitor will

I am looking to recruit a new PhD student in the area of computational modeling of soft active materials.  The position will begin as early as January 2014, or alternatively in September 2014.  Requirements for this position including the ability to program in C++, knowledge of nonlinear finite element methods and continuum mechanics, and a good background in solid mechanics.  If interested, please contact me at parkhs(at)bu.edu, with a copy of a CV and a description of your previous research experience.

<http://www.sciencedirect.com/science/article/pii/S0045782513000790>

Soft dielectric elastomer is able to generate an
electromechanical response in terms of reversible shape
changing, which is a muscle-like behavior. The deformation
and electromechanical stability of dielectric elastomers,
classified by their deformation modes, uniaxial extension,
equal biaxial expansion and pure shear, are investigated.
Pull-in instability occurs in equal biaxial and uniaxial modes
at a small stretch ratio, while the pure shear mode features
wrinkling instability after a large stable deformation. The

Recently accepted for publication in Soft Matter:

(http://pubs.rsc.org/en/Content/ArticleLanding/2013/SM/C2SM27375F)

(http://dx.doi.org/10.1039/c2sm27375f)

The dielectric constant is an essential electrical parameter to the
achievable voltage-induced deformation of the dielectric
elastomer. This paper primarily focuses on the temperature
dependence of the dielectric constant (within the range of 173 K
to 373 K) for the most widely used acrylic dielectric
elastomer (VHB 4910). First the dielectric constant was investigated
experimentally with the broadband dielectric spectrometer
(BDS). Results showed that the dielectric constant first increased
with temperature up to a peak value and then dropped to a
relative small value. Then by analyzing the fitted curves, the Cole–Cole
dispersion equation was found better to characterize the
rising process before the peak values than the Debye dispersion

Dielectric elastomer transducers are often subject to large tensile stretches and are susceptible to rupture. Here we carry out an experimental study of the rupture behavior of membranes of an acrylic dielectric elastomer (VHB 4905). Pure-shear test specimens are used to measure force-displacement curves, using samples with and without pre-cracks. We find that introducing a pre-crack into a membrane drastically reduces the stretch at rupture. Furthermore, we measure the stretch at rupture and fracture energy using samples of different heights at various stretch-rates. The stretch at rupture is found to decrease with sample height, and the fracture energy is found to increase with stretch-rate.
This paper has appeared in the Journal of Applied Physics and can be downloaded from: