Design, fabrication, and modeling of an electric-magnetic self-folding sheet

A concept recently proposed by the authors is that of a multifield sheet that folds into several distinct shapes based on the applied field, be it magnetic, electric, or thermal. In this paper the design, fabrication, and modeling of a multi-field bifold is presented that utilizes magneto-active elastomer (MAE) to fold along one axis and P(VDF-TrFE-CTFE) terpolymer to fold along the other axis. In prior work a dynamic model of self-folding origami was developed which simulated the effect of magneto-active materials on origami-inspired designs. This dynamic model is extended to include the effect of electroactive polymers (EAP) by approximating them as combinations of torques. The accuracy of this approximation is validated using experimental data from a terpolymer-actuated design known as the barking dog. After adjusting crease stiffness within the dynamic model, it shows good correlation with experimental data, indicating that the developed EAP approximation is accurate. With the capabilities of the dynamic model improved by the EAP approximation method and a refined MAE approximation, the multi-field bifold can be accurately modeled. The model is compared to experimental data obtained from the fabricated multi-field bifold, and is found to predict well the fold angles of the sample. This validation is a first step to the simulation, design, and fabrication of more complicated multi-field sheets.