Micromechanics of Interactions Between Hard Magnetic Particles and Soft Matrix on Magneto-Mechanical Actuation

该奖项研究的是硬磁软活性材料磁机械驱动的微观力学。这些材料利用嵌入的硬磁性颗粒和外加磁场之间的相互作用来实现对软基材料的驱动。硬磁软活性材料是一类可以快速、可逆、远程激活的新型软活性材料。这些材料是嵌入软基中的硬磁性颗粒的复合材料。驱动是通过将磁性颗粒中的磁性微力矩传递到软基上来实现的。它们具有不受约束的复杂变形、快速的响应速度和可逆驱动等优点，在软机器人和生物医学设备中显示出广阔的应用前景。然而，由于这些材料相对较新的发展，对微观行为如何驱动宏观材料驱动的了解仍不清楚。这项工作将在微观力学水平上为硬磁软活性材料的磁力驱动机理提供基础知识，为宏观有效性能与微观结构之间的联系提供理论依据，以及对拉伸软化效应如何影响宏观驱动的理解。这个项目将提供关于粒子-粒子和粒子-基质相互作用如何通过使用微观力学方法单独和集体地对驱动做出贡献的新知识。新的知识将被用于理论模型中，以获得有效的剩余磁通密度。这项工作还将研究穆林斯效应是如何影响驱动的。理论模型、模拟和实验测试的协同发展将为研究微填料对刺激响应型软基复合材料的微观力学和宏观力学响应提供有效的平台。该项目将利用软机器人中令人兴奋的硬磁软活性材料演示作为工具来促进STEM教育，重点是来自代表不足的群体的学生以及K-12教育。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award studies the micromechanics of the magneto-mechanical actuation of hard-magnetic soft active materials. These materials utilize the interactions between embedded hard-magnetic particles and applied magnetic fields to achieve actuation of the soft matrix materials. Hard-magnetic soft active materials are a new group of soft active materials that can be activated rapidly, reversibly, and remotely. These materials are composites with hard-magnetic particles embedded in soft matrices. The actuation is achieved through transferring the magnetic micro-torques in the magnetic particles to the soft matrix. They have demonstrated many advantages, such as untethered complex deformation, rapid response speed, and reversible actuation, showing promising potential for applications in soft robots and biomedical devices. However, due to the relatively new development of these materials, the understanding of how the microscopic behavior drives the macroscopic material actuation remains unknown. The work will provide the fundamental knowledge of the magneto-mechanical actuation mechanism of hard-magnetic soft active materials at the micromechanics level, the theory that can connect macroscopic effective properties with microscopic structures, and the understanding of how the stretch-induced softening effect can affect the macroscopic actuation. This project will provide new knowledge on how particle-particle and particle-matrix interactions can contribute individually and collectively to the actuation by using a micromechanics approach. The new knowledge will be used in a theoretical model to obtain the effective residual magnetic flux density. The work will also investigate how the Mullins effect affects actuation. The synergetic development on theoretical models, simulations and experimental testing will provide an effective platform to correlate the micromechanics and macroscale mechanical response of stimuli-responsive soft composites with micro-fillers. The project will use the exciting demonstrations of hard-magnetic soft active materials in soft robots as vehicles to promote STEM education with a focus on students from underrepresented groups as well as K-12 education.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.