Abstract
Magneto-active elastomers (MAE) are capable of achieving large deflections when actuated using an external magnetic field. Desired shape changes are achieved by judiciously designing a unimorph actuator comprised of an active MAE layer and a passive material substrate. In this paper, an analytical model is developed to predict the shape change of an MAE unimorph actuator that is segmented along its length. The shape change performance of a unimorph actuator consisting of polydimethylsiloxane (PDMS) embedded with barium hexaferrite (BHF) particles and a passive substrate of Scotch tape is investigated for different segmented geometric configurations.
An Euler-Bernoulli model is developed to predict the free deflection and blocked force of the segmented unimorph given the geometric information, properties of the materials, and the external magnetic field strength. A numerical approach is also developed to account for consecutive segments and different conditions for each segment as the unimorph bends. The conditions include the spatial variation of the magnetic field and the dependence of actuation torque on the bending angle. The model is validated with experiments under the same conditions, and the outcomes show good agreement with the experimental results. The validated model is used in a parametric study to assess the effects of the geometric parameters, material properties, and the magnitude of the magnetic field on the shape change.
