CAREER: Multiphysics Mechanics of Magnetic Shape Memory Polymers

该学院早期职业发展计划（Career）资助研究磁性形状记忆聚合物的多种物理行为。形状记忆效应指的是材料在磁场和机械能的作用下记忆和恢复预先设定形状的能力。这些材料是在形状记忆聚合物基体中嵌入磁性颗粒的复合材料。他们利用叠加的交变磁场和直接磁场来调节材料的刚度和形状变化驱动。它们在一个材料系统中结合了不受束缚的快速可逆转换、形状锁定能力和可重新编程性，在软机器人、柔性电子设备和用于微创手术的生物医学设备中具有潜在的应用前景。然而，这些材料复杂的磁-热-粘弹性行为使得使用这些材料的应用设计非常具有挑战性。这项工作的成功将导致对磁性形状记忆聚合物的系统理解，描述磁热粘弹性行为的材料模型以及加速应用设计的多物理场仿真平台。这项工作将通过3D打印磁驱动软机器人为中学生提供动手互动的多学科研究经验。这项工作还将通过当地的科学与工业科学节和俄亥俄州立大学STEAM工厂富兰克林星期五活动向K-12学生和公众展示材料研究。软质活性材料应用广泛，但存在致动速度慢、致动不可逆、无形状锁定等局限性。磁性形状记忆聚合物通过将快速磁致动与聚合物中的形状记忆效应相结合，克服了这些限制。这些材料利用交变磁场控制温度，利用直流磁场驱动材料。磁致动与热粘弹性材料性能的耦合需要深入的基础力学研究。该奖项将为磁性颗粒和磁性颗粒-聚合物基质之间的相互作用如何改变聚合物的热粘弹性和形状记忆行为提供新的理解。这些理解将有助于建立磁热粘弹性固体的热力学框架。新的框架可以清晰地描述复杂的多物理场过程，并指导磁热粘弹性固体的新本构模型的发展。将该本构模型应用于有限元分析中，模拟具有复杂几何形状和复杂载荷条件的磁性形状记忆聚合物的磁致动和热致动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development Program (CAREER) grant investigates multiple physical behaviors of magnetic shape memory polymers. The shape memory effect refers to the ability of a material to remember and recover a pre-programmed shape in response to a combination of magnetic and mechanical fields. These materials are composites with embedded magnetic particles in shape memory polymer matrices. They utilize superposed alternating and direct magnetic fields to regulate the stiffness and shape changing actuation of the materials. They combine untethered fast and reversible transformation, shape-locking ability, and reprogrammability in one material system and have potential applications in soft robots, flexible electronics, and biomedical devices for minimum invasive surgery. However, the complicated magneto-thermo-viscoelastic behaviors of these materials make the design of applications using these materials very challenging. The success of this work will lead to a systematic understanding of the magnetic shape memory polymer, a material model to describe the magneto-thermo-viscoelastic behavior and a multiphysics simulation platform to accelerate the design of applications. This work will provide hands-on interactive multi-disciplinary research experience for middle and high school students through 3D Printed Magnetically Actuated Soft Robots. This work will also demonstrate material research to K-12 students and the general public through the local Science and Industry Science Festival and the Ohio State University STEAM factory Franklinton Friday Events. Soft active materials are widely used but have limitations such as slow actuation speed, irreversible actuation, or no shape-locking. Magnetic shape memory polymers overcome these limitations by integrating rapid magnetic actuation with shape memory effects in polymers. These materials use the alternative current magnetic field to control the temperature and the direct current magnetic field to actuate the materials. The coupling of magnetic actuation with thermoviscoelastic material behavior demands intensive fundamental mechanics research. This CAREER award will provide new understandings on how the interactions among magnetic particles and magnetic particles-polymer matrix can alter the thermoviscoelastic and shape memory behavior of a polymer. These understandings will enable the establishment of a thermodynamic framework for magneto-thermo-viscoelastic solids. The new framework can provide a clear description of the complicated multiphysics processes and guide the development of a new constitutive model for magneto-thermo-viscoelastic solids. The new constitutive model will be implemented into finite element analysis to simulate the magnetic and thermal actuation of magnetic shape memory polymers with complicated geometry and complicated loading conditions.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.