Embedding small magnetic particles within soft rubber materials enables mechanical systems to actively change their state. We call such systems actuated. Magnetic actuation is especially interesting, because it allows for control at a distance, without attached wires or cables. Two examples are shown in the Figure (left), where magnetically actuated soft hairs propel small robots, or steer fluid within fluidic systems. Another example is a soft robot designed to deliver drugs inside a human body, see the Figure (middle).
Currently, one of the challenges is overall miniaturization, which does not allow for using standard neodymium magnets and requires use of more advanced magnetic particles. This applies especially in 3D printing, where neodymium particles cluster and clog while printing. An advanced alternative is shown in the Figure (right), where antiferromagnetic particles as small as 100 nm can be used.
In this project, we focus on development of a suitable constitutive model that will accurately describe mechanical behavior of rubber materials with embedded antiferromagnetic particles, motivated by previous work [3]. Starting from a hyperelastic formulation for rubber materials, effect of magnetic particles will be included. The tasks within this project will involve, but are not limited to:
Understanding hyperelastic models for large-deformation rubber-like materials and Stoner-Wohlfarth model capturing behavior of antiferromagnetic particles.
Combination of both models to create an effective description of magnetoactive continuum.
Implementation and testing within a numerical FEM framework.
Validation against experimental data (optional).
References
[1] Shape-programmable miniscule robots. https://www.rdworldonline.com/shape-programmable-miniscule-robots/
[2] Soft robot transports and delivers drugs inside the gut. https://www.advancedsciencenews.com/soft-robot-transports-and-delivers-drugs-inside-the-gut/
[3] R. Zhao, Y. Kim, S. A. Chester, P. Sharma, and X. Zhao, ‘Mechanics of hard-magnetic soft materials’, Journal of the Mechanics and Physics of Solids, vol. 124, pp. 244–263, Mar. 2019, doi: 10.1016/j.jmps.2018.10.008.
[4] J. Li, P. van Nieuwkerk, M. A. Verschuuren, B. Koopmans, and R. Lavrijsen, ‘Substrate conformal imprint fabrication process of synthetic antiferromagnetic nanoplatelets’, Applied Physics Letters, vol. 121, no. 18, p. 182407, Nov. 2022, doi: 10.1063/5.0100657.
