Spontaneous change of symmetry in a magnetoactive elastomer beam at its critical bending induced by a magnetic field

Abstract

The features of the critical bending deformation and magnetization of a magnetoactive elastomer (MAE) beam with a fixed end in a transverse uniform magnetic field have been studied. After the beam reaches a critical bending, the symmetry of the beam shape and the symmetry of the MAE magnetic state change spontaneously. At the critical point, a continuous transition from the highly symmetric magnetic state in the unbent MAE beam to the low symmetric magnetic state in the bent MAE beam (this is the angular state with the effective magnetization inclined to the field) takes place. The beam bending occurs due to the gain in the magnetic energy of the beam. The formation of an angular magnetic state in it has a magnetoelastic origin and is characterized by the critical behavior of the mutually related bending and longitudinal effective magnetization of the MAE, but it is the magnetization that plays the role of order parameter. Furthermore, there is no longitudinal magnetization in the absence of bending and, vice versa, there is no bending in the absence of longitudinal magnetization. The influence of a low remanent magnetization, which eliminates the uncertainty in the bending direction, on the critical bending has been analyzed. The role of the magnetorheological effect, which affects the critical field magnitude and leads to the appearance of field-induced bending hysteresis near the critical point, has also been elucidated.

Signatures and characterization of dominating Kerr nonlinearity between two driven systems with application to a suspended magnetic beam

“…It could be interesting to study the buckling of a magnetic beam as an orientational phase transition [1], similarly to Ref. [69].…”

Analytical modeling of a magnetoactive elastomer unimorph

“…From this data, two functions are fit to describe the dependence of m mH on H, as noted in figure 5 [40]. Although the MAE unimorph is magnetically anisotropic due to the demagnetizing field and the dipole-dipole interaction [41], the direction of the induced magnetization for the beam-like MAE unimorph is assumed to be aligned with the length of the unimorph from tip to base. For this case study, a NdFeB Grade 52 cylindrical permanent magnet (K&J Magnetics, Inc.) with a length of 5 cm and a diameter of 5 cm is used to provide the external magnetic field.…”

Low Magnetic Field Induced Extrinsic Strains in Multifunctional Particulate Composites: An Interrupted Mechanical Strengthening in 3D-Printed Nanocomposites

“…Magneto-active polymers (e.g., magnetostrictive) are a class of composite materials that consist of a polymer embedded with magnetisable particles, driven by a straininduced mechanism called magnetic polarisation owing to the dipolar displacement occurring in magnetic and piezomagnetic (magnetostrictive) materials under magnetic field exposure [1][2][3][4][5][6][7] serving deformation in soft robotics and actuations [8]. Magnetostriction occurs in almost all ferromagnetic materials such as iron, cobalt, nickel and their corresponding alloys [9].…”