Work

Viscoelastic strain response of dielectric elastomer materials for artificial muscles

Year: 2025

Type: article

Abstract: Dielectric elastomer actuators (DEAs) are promising candidates for artificial muscle systems due to their lightweight structure, large deformation capabilities, and rapid response to electrical stimulation. This work investigates the electro-mechanical performance of cross-linked synthetic polychloroprene (CR), polyurethane (PUR), and hydrogenated acrylonitrile-butadiene rubbers (HNBR) as alternative dielectric elastomers (DEs) for DEAs. These elastomers demonstrated enhanced dielectric constants of ε r = 8.5 (CR), ε r = 6.4 (PUR), and ε r = 10 (HNBR) compared to ε r values of conventional DEs ε r = 2.3 (Elastosil 2030) and ε r = 4.7 (VHB 4910). Circular DEAs were manufactured to investigate the time-dependent actuation strain at a low excitation field strength of 16 V μm −1 . CR showed a response time of 1.2 s, indicating potential for fast-response applications. In contrast, the response time of PUR and HNBR is significantly higher (ca. 5 s) caused by a viscoelastic creep deformation. At a field strength of 16 V μm −1 the electro-active strain of all alternative DEs exceeds that of commercially Elastosil 2030. Among the alternative materials, HNBR exhibits the highest electro-active radial strain (2.2%) at the highest tested field strength of 26 V μm −1 . A linear-elastic model and a viscoelastic model were implemented in LTspice using electro-mechanical analogies to simulate the actuator behavior. While the linear model effectively estimated the strain magnitude, the viscoelastic model allowed a more accurate representation of the time-dependent actuation dynamics. The results highlight the potential of CR, PUR, and HNBR as viable alternatives for tailored DEA applications across varying actuation speed and strain requirements.

Source: Materials Research Express

DOI: 10.1088/2053-1591/ae1796