Porte Elze, Eristoff Sophia, Agrawala Anjali, Kramer-Bottiglio Rebecca
Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut, USA.
Department of Mechanical Engineering, University College London, London, United Kingdom.
Soft Robot. 2024 Feb;11(1):118-130. doi: 10.1089/soro.2023.0004. Epub 2023 Sep 5.
Soft robots are predicted to operate well in unstructured environments due to their resilience to impacts, embodied intelligence, and potential ability to adapt to uncertain circumstances. Soft robots are of further interest for space and extraterrestrial missions, owing to their lightweight and compressible construction. Most soft robots in the literature to-date are made of elastomer bodies. However, limited data are available on the material characteristics of commonly used elastomers in extreme environments. In this study, we characterize four commonly used elastomers in the soft robotics literature-EcoFlex 00-30, Dragon Skin 10, Smooth-Sil 950, and Sylgard 184-in a temperature range of -40°C to 80°C and humidity range of 5-95% RH. We perform pull-to-failure, stiffness, and stress-relaxation tests. Furthermore, we perform a case study on soft elastomers used in stretchable capacitive sensors to evaluate the implications of the constituent material behavior on component performance. We find that all elastomers show temperature-dependent behavior, with typical stiffening of the material and a lower strain at failure with increasing temperature. The stress-relaxation response to temperature depends on the type of elastomer. Limited material effects are observed in response to different humidity conditions. The mechanical properties of the capacitive sensors are only dependent on temperature, but the measured capacitance shows changes related to both humidity and temperature changes, indicating that component-specific properties need to be considered in tandem with the mechanical design. This study provides essential insights into elastomer behavior for the design and successful operation of soft robots in varied environmental conditions.
由于软机器人对冲击具有弹性、具备具身智能以及具有适应不确定环境的潜在能力，预计它们将在非结构化环境中良好运行。软机器人因其轻质且可压缩的结构，在太空和外星任务中更受关注。迄今为止，文献中的大多数软机器人由弹性体机身制成。然而，关于常用弹性体在极端环境下的材料特性的数据有限。在本研究中，我们对软机器人领域文献中常用的四种弹性体——EcoFlex 00 - 30、Dragon Skin 10、Smooth - Sil 950和Sylgard 184——在-40°C至80°C的温度范围以及5 - 95%相对湿度的环境下进行了特性表征。我们进行了拉伸至破坏、刚度和应力松弛测试。此外，我们对用于可拉伸电容式传感器的软弹性体进行了案例研究，以评估组成材料行为对部件性能的影响。我们发现所有弹性体都表现出温度依赖性行为，随着温度升高，材料通常会变硬，破坏应变降低。应力松弛对温度的响应取决于弹性体的类型。在不同湿度条件下观察到有限的材料效应。电容式传感器的机械性能仅取决于温度，但测量的电容显示出与湿度和温度变化都相关的变化，这表明在机械设计时需要同时考虑部件特定的特性。本研究为在各种环境条件下设计和成功运行软机器人提供了关于弹性体行为的重要见解。
