Abstract
In recent years, dielectric elastomer actuators (DEAs) have been widely used in soft robots and artificial bio-medical applications. Most DEAs are composed of a thin dielectric elastomer layer sandwiched between two compliant electrodes. DEAs vary in their design to provide bending, torsional, and stretch/contraction motions under the application of high external voltages. Most compliant electrodes are made of carbon powders or thin metallic films. In situations involving large deformations or improper fabrication, the electrodes are susceptible to breakage and increased resistivity. The worst cases result in a loss of conductivity and functional failure. In this study, we developed a method by which to exploit stretchable metallic springs as compliant electrodes for cylindrical DEAs. This design was inspired by the extensibility of mechanical springs. The main advantage of this approach is the fact that the metallic spring-like compliant electrodes remain conductive and do not increase the stiffness as the tube-like DEAs elongate in the axial direction. This can be attributed to a reduction in thickness in the radial direction. The proposed cylindrical structure is composed of highly-stretchable VHB 4905 film folded within a hollow tube and then sandwiched between copper springs (inside and outside) to allow for stretching and contraction in the axial direction under the application of high DC voltages. We fabricated a prototype and evaluated the mechanical and electromechanical properties of the device experimentally using a high-voltage source of 9.9 kV. This device demonstrated a non-linear increase in axial stretching with an increase in applied voltage, reaching a maximum extension of 0.63 mm (axial strain of 2.35%) at applied voltage of 9.9 kV. Further miniaturization and the incorporation of compressive springs are expected to allow the implementation of the proposed method in soft micro-robots and bio-mimetic applications.
Highlights
Recent developments in soft robots and artificial biomimetic structures have greatly increased interest in dielectric bio-compatible elastomers capable of producing large deformations
Recent applications include tunable lenses [1], micro-pumps [2], energy harvesting [3], transducers [4], soft robots [5,6,7,8], and artificial muscles [9,10,11] Most dielectric elastomer actuators (DEAs) are composed of stretchable materials, such as polymers sandwiched between two compliant electrodes that alter their shape under an applied external electrical stimuli
Under high voltage excitation during the first 60 s of each cycle, the cylindrical DEA extended to its maximum
Summary
Recent developments in soft robots and artificial biomimetic structures have greatly increased interest in dielectric bio-compatible elastomers capable of producing large deformations. These devices have been widely used in actuators and sensors. Under an applied external voltage (stimulus), the electrostatic force exerted in the radial directions by the compliant electrodes squeezes the elastomer, which causes expansion in the axial direction Different cylindrical configurations, such as tubes [12,13,14,15], helixes [16], and rolls [17], have been investigated to allow for bending and torsional and stretching/contraction motions. In addition to the axial deformations of cylindrical DEAs, a folded structure [20] and a multi-layer stack [21] have been developed to provide linear motion
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
