Analytical modeling of a magnetoactive elastomer unimorph
Analytical modeling of a magnetoactive elastomer unimorph
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DOI：
10.1088/1361-665x/acece7
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发表时间：
2023-08
影响因子：
4.1
通讯作者：
Tan Pan;Rui Leng;O. Uitz;C. Seepersad;Z. Ounaies;M. Frecker
中科院分区：
文献类型：
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作者：
Tan Pan;Rui Leng;O. Uitz;C. Seepersad;Z. Ounaies;M. Frecker
磁活性弹性体(MAE)在外加磁场的驱动下，能够产生大变形、形状规划和中等大的驱动力。这些功能使软夹爪、生物医学设备和执行器等应用成为可能。为了便于复杂的形状变形和更大的运动范围，单晶片可以设计成具有不同的几何形状，表现出空间上不同的多材料特性，并由非均匀的外部磁场驱动。为了预测在这些复杂条件下的驱动性能，基于大变形梁理论建立了分段MAE单晶片的分析模型。空间变化磁场的影响可以用分段有效扭矩来近似。该模型适应了空间上不同浓度的磁性粒子，并通过适应关于磁场下感应磁化的大小和方向的不同假设，区分了硬磁性粒子和软磁性粒子的驱动机制。为了验证模型预测的准确性，用不同的磁性粒子和基质材料进行了四个案例研究。为验证模型的有效性，对驱动性能进行了实验测量。结果表明，实验测量结果与模型预测结果吻合较好。通过进一步的参数研究，研究了颗粒的磁性和外加磁场对自由偏转的影响。此外，通过局部改变几何和材料属性，演示了单晶片执行器的复杂形状编程。
Magnetoactive elastomers (MAEs) are capable of large deformation, shape programming, and moderately large actuation forces when driven by an external magnetic field. These capabilities enable applications such as soft grippers, biomedical devices, and actuators. To facilitate complex shape deformation and enhanced range of motion, a unimorph can be designed with varying geometries, behave spatially varying multi-material properties, and be actuated with a non-uniform external magnetic field. To predict actuation performance under these complex conditions, an analytical model of a segmented MAE unimorph is developed based on beam theory with large deformation. The effect of the spatially-varying magnetic field is approximated using a segment-wise effective torque. The model accommodates spatially varying concentrations of magnetic particles and differentiates between the actuation mechanisms of hard and soft magnetic particles by accommodating different assumptions concerning the magnitude and direction of induced magnetization under a magnetic field. To validate the accuracy of the model predictions, four case studies are considered with various magnetic particles and matrix materials. Actuation performance is measured experimentally to validate the model for the case studies. The results show good agreement between experimental measurements and model predictions. A further parametric study is conducted to investigate the effects of the magnetic properties of particles and external magnetic fields on the free deflection. In addition, complex shape programming of the unimorph actuator is demonstrated by locally altering the geometric and material properties.