Dielectric elastomers are novel soft smart material that could deform sustainably when subjected to external electric field. That makes dielectric elastomers promising materials for actuators. In this paper, a spring-roll actuator that would bend when a high voltage is applied was fabricated based on dielectric elastomer. Using such actuators as active parts, the flexible grippers and inchworm-inspired crawling robots were manufactured, which demonstrated some examples of applications in soft robotics. To guide the parameters design of dielectric elastomer based spring-roll bending actuators, the theoretical model of such actuators was established based on thermodynamic theories. The initial deformation and electrical induced bending angle of actuators were formulated. The failure of actuators was also analyzed considering some typical failure modes like electromechanical instability, electrical breakdown, loss of tension and maximum tolerant stretch. Thus the allowable region of actuators was determined. Then the bending angle-voltage relations and failure voltages of actuators with different parameters, including stretches of the dielectric elastomer film, number of active layers, and dimensions of spring, were investigated. The influences of each parameter on the actuator performances were discussed, providing meaningful guidance to the optical design of the spring-roll bending actuators.
In this paper, the characterization and electromechanical stability behavior of nano sized BaTiO3 particle filled
dielectric elastomer has been analyzed experimentally and theoretically. The free energy function involving a new
dielectric energy density function and Mooney-Rivlin elastic strain energy function has been used to carry out the
analysis. To give a comprehensive dielectric energy function, the influence of the BaTiO3 weight fraction on the
dielectric property of the dielectric elastomer has been considered. The analytical results show that with the
increasing weight fraction of BaTiO3 or the electrostrictive factor, the critical electric field of silicone elastomer
decreases, i.e. the elastomer’s stability is reduced. Meanwhile, with the increasing material constant ratio k which is
the ratio of the two material constants appeared in the Mooney-Rivilin elastic strain energy function, the critical
nominal electric field will increase. These results are useful in not only helping us to understand the influence of the
filled nano-BaTiO3 particles on the electromechanical stability of silicone dielectric elastomer, but also giving great
guidance to obtain specific dielectric elastomer actuators to meet the demand of users by changing the dielectric
property of the elastomer.
Dielectric elastomer is a kind of smart soft material that has many advantages such as large deformation, fast response,
light weight and easy synthesis. Subject to a high voltage, dielectric elastomer film will deform sustainably. These
features make dielectric elastomer a suitable material for actuators. This paper discussed a spring-roll bending actuator of
dielectric elastomer. An actuator based on dielectric elastomer that could bend when applied a high voltage was
fabricated. Based on thermodynamics theories, a theoretical model of dielectric elastomer bending actuator was
established and the initial deformation and bending deformation of bending actuator was formulated. Most parameters
used in formulas could be obtained from fabrication process or test data and theoretical prediction with these parameters
explained the experimental phenomena well. Also, the allowable area of bending actuator is determined considering
several failure models including electromechanical instability, electrical breakdown and tensile rupture.