Soft dielectric elastomers respond to electric stimuli by undergoing large deformations and changes in their material properties. The actuation with deformable electrodes attached to the material originates Coulomb and dipole forces that convert the electric field into a mechanical response. Applications at large deformations can entail crack onset and propagation. Within this context, the response of a soft polymer to an applied electric field may serve to influence the fracture behavior of such materials, potentially enhancing it. Here we explore the fracture performance of an ultra-soft dielectric elastomer. To do so, we conduct tensile tests while applying electrical actuation on samples with pre-cuts. Additionally, we examine the elastomer filled with piezoelectric BaTiO3 particles to ameliorate the fracture performance beyond the limits observed in the unfilled material. In conjunction with the experiments, we employ a bespoke fracture phase-field model to analyze the stress triaxiality near the crack tip. The results indicate that the electric actuation induces beneficial crack tip blunting and stress de-concentration, enhancing the fracture toughness up to a 125 % and delaying crack propagation. Our work provides a route for applications of soft dielectric elastomers that require improved fracture properties or, more broadly, the modulation of fracture behavior.

软介电弹性体通过发生大的变形和材料特性的变化来响应电刺激。连接到材料的可变形电极的驱动产生库仑力和偶极力，将电场转换成机械响应。大变形的应用可能会导致裂纹的产生和扩展。在这种情况下，软聚合物对施加电场的响应可能会影响此类材料的断裂行为，并可能增强其断裂行为。在这里，我们探讨了超软介电弹性体的断裂性能。为此，我们在对预先切割的样品施加电驱动的同时进行拉伸测试。此外，我们还检查了填充有压电 BaTiO3 颗粒的弹性体，以改善断裂性能，使其超出未填充材料中观察到的极限。结合实验，我们采用定制的断裂相场模型来分析裂纹尖端附近的应力三轴性。结果表明，电驱动会产生有益的裂纹尖端钝化和应力分散，将断裂韧性提高至 125  %，并延迟裂纹扩展。我们的工作为需要改善断裂性能或更广泛地调节断裂行为的软介电弹性体的应用提供了一条途径。