Design parameters for magneto-elastic soft actuators

Abstract

Novel soft actuators can be designed from ferrogels by combining the elastic behavior of a polymer matrix with the magnetic properties of a magnetic filler. A thorough understanding of the mechanical behavior of ferrogel actuation is essential for optimizing actuator performance. For actuation by linear magnetostriction, the influence of geometrical parameters on the onset and magnitude of hysteretic loss, the range for the continuous deformation ratio, the rate of change of the deformation ratio with respect to the field strength, and the saturation elongation were modeled. These results demonstrate that geometrical design parameters such as specimen length, aspect ratio, and distance from the magnetic field source can be used to tune the performance of ferrogels.

Synthesis and characterization of uniaxial ferrogels with Ni nanorods as magnetic phase

“…The correction factor C(n) for nanorods is here approximated by the value for prolate ellipsoidal particles [26]. Assuming a Poisson ratio of 0.5, which is a reasonable approximation for rubber-like materials [6], and the aspect ratio of n ¼8.54, a value of C(n)¼10.39 is obtained for the nanorods of this study. It should be noticed that the linear relationship T mech po is an approximation for small o only.…”

“…As an example, when a ferrogel is exposed to a magnetic field gradient, the magnetophoretic force acting on the particles is transferred to the polymer network leading to a large and rapid deformation of the ferrogel body. The capability to perform mechanical work suggests applications of such materials as soft actuators [6,7]. It is obvious that the response of a ferrogel to a magnetic stimulus is determined by the mechanical compliance of the gel matrix and by the volume fraction, distribution and the intrinsic magnetic properties of the embedded nanoparticles.…”

Enhanced microactuation with magnetic field curing of magnetorheological elastomers based on iron–natural rubber nanocomposites

“…Attempts to make MR elastomer-based microactuator devices had met with only little success. 18 Because of high magnetic permeability, low remanent magnetization and high saturation magnetization, iron particles are used as fillers for MR elastomers and thus it provides high interparticle attraction and produce large MR effect. In the present investigation, iron-based MR elastomers have been fabricated using a modified curing technique.…”

Facile route to preparation of Fe-Co microclusters with highly enhanced magnetic performances

“…Fe-Co alloys are used in a variety of applications such as targeted drug delivery, cancer therapy [9,10], highfrequency power applications [11], magnetic-resonance imaging [12], electromagnetic EM-wave absorption [13,14], and magnetoelastic soft actuators [15]. The synthesis of Fe-Co through chemical synthesis techniques has been a subject of interest and attempted through sol-gel method [16], hydrogen reduction [17], thermal decomposition [18,19], thermolysis [20,21], borohydride reduction [22], coprecipitation [23], and alkalide reduction [24].…”