Development and Validation of a Dynamic Model of Magneto-Active Elastomer Actuation of the Origami Waterbomb Base

Abstract

Of special interest in the growing field of origami engineering is self-folding, wherein a material is able to fold itself in response to an applied field. In order to simulate the effect of active materials on an origami-inspired design, a dynamic model is needed. Ideally, the model would be an aid in determining how much active material is needed and where it should be placed to actuate the model to the desired position(s). A dynamic model of the origami waterbomb base, a well-known and foundational origami mechanism, is developed using adams 2014, a commercial multibody dynamics software package. Creases are approximated as torsion springs with both stiffness and damping. The stiffness of an origami crease is calculated, and the dynamic model is verified using the waterbomb. An approximation of the torque produced by magneto-active elastomers (MAEs) is calculated and is used to simulate MAE-actuated self-folding of the waterbomb. Experimental validation of the self-folding waterbomb model is performed, verifying that the dynamic model is capable of accurate simulation of the fold angles.

Elasticity and stability of shape-shifting structures

“…On a slightly larger scale, there is interest in the micro-and nanoelectromechanical (MEMS and NEMS, respectively) communities to use the rapid snap-through of arches and shells in electromechanical systems [119] for accelerometers [120], or as a means to rapidly change a surface's texture or optical properties [88]. The precise placement of folds in thin sheets can generate a wide range of multistable structures, with the most fundamental being the waterbomb [121,122,123,3], which has generic bistability for any number of creases [3]. In addition to traditional folding and cutting techniques, programming creases into a material through spatial variations in its thickness can enable bistability in folded shells -cylinders, spheres, or saddles [124].…”

Characterization of Self-Folding Origami Structures Using Magneto-Active Elastomers

“…The role of the active materials in origami engineering is to generate and mimic the forces of human interaction that bend or fold the structures. Some examples of active materials employed in origami engineering are shape memory alloys (SMA) and shape memory polymers (SMP) for thermally activated self-folding [16,17], polyelectrolytes for chemically activated [17,18], dielectric elastomers (DE) and polyvinylidene fluoride (PVDF)-based terpolymer for electrically activated [16,17], [19], and MAEs for magnetically activated [17,20]. In addition to the above materials, photo activated materials are also used to bend and fold Figure 2.…”

“…To determine which active material is most suitable for self-folding, the actuation strain and stress of the material as well as the ability to generate or manipulate the desired field for actuation are considered [17]. Furthermore, the response time, frequency of response capability, and the bi-directionality of the response can also be taken into consideration [20]. Bidirectional behavior refers to the material's ability to displace in both the positive and negative direction depending on the source of actuation [20].…”

“…Furthermore, the response time, frequency of response capability, and the bi-directionality of the response can also be taken into consideration [20]. Bidirectional behavior refers to the material's ability to displace in both the positive and negative direction depending on the source of actuation [20].…”

“…They are useful in origami engineering because of their high specific elastic energy density (3.4 J/g), large strain response (>300%), fast response time (<1sec), high actuation stress (up to 8MPa) and high electromechanical coupling efficiency (60-90%) [15]. However, DEs are not bidirectional [20].…”