Effect of Mould Orientation on the Field-Dependent Properties of MR Elastomers under Shear Deformation

Abstract

In this study, magnetorheological elastomer (MRE) was fabricated using an electromagnetic device with a new configuration mold at the orientation of 0°, 45° and 90°. This new curing concept enhanced the alignment of carbonyl iron particles (CIPs) within the silicone matrix in the presence of silicone oil (SO) during solidifying, by eliminating air gaps to prevent magnetic flux losses. Using a mold made of steel, which is a magnetic material, the mold functions as a guide for concentrated magnetic flux of 0.315 T to pass through the MRE sample. Scanning electron microscopy (SEM) was used to observe the surface morphology of the fabricated MRE samples particularly the alignment of the CIPs. The field-dependent dynamic properties of the MREs were measured using a rheometer. The analysis implied that the effectiveness of the MRE operating under shear deformation with this curing concept provided the highest magneto-induced modulus of 1.01 MPa when a 45° orientation mold is used, with relative magnetorheological (MR) effect value up to 918%, followed by 0° mold orientation with 0.79 MPa magneto-induced modulus and 646% relative MR effect. The high modulus properties offered by this MRE are believed to be potentially useful in industrial applications where a high range of stiffness is required particularly in the shear direction.

Experimental and theoretical investigation on magnetorheological elastomers containing carbonyl iron particles coated with silane coupling agent

“…Additionally, Tian and Nakano [18] created anisotropic MREs with varying silicone oil content and concluded that MREs with 15% silicone oil demonstrated a higher maximum MR effect, attributable to lower zero-field storage and loss modulus. The beneficial role of silicone oil in MREs was also supported by other studies [19][20][21]. Ronzova et al [22] believed that the surface modification of magnetic particles with various organosilanes could markedly enhance the MR properties without compromising the magnetization intensity of the core-shell particles.…”

“…In equation (18), G m (H, 1) is the magneto-induced modulus when driving frequency is 1 Hz under magnetic field strength H, s is a parameter independent of magnetic field strength. In equation (19), δ is a dimensionless model parameter, ϕ is the volume fraction of CIPs,…”

Particle mobility and macroscopic magnetorheological effects for polyurethane magnetic elastomers

“…It is widely known that the elasticity decreased with the plasticizer concentration, resulting in a significant change in the storage modulus by magnetic fields. [22][23][24][25][26] Also, it is well-known that the elasticity decreased with decreasing cross-linking density, resulting in a significant MR effect. Actually, Sun and Liu et al demonstrated the effect of cross-linking density on the MR effect using polymethyl siloxane gels cross-linked by boric acid.…”

Tensile Properties of Isotropic and Anisotropic Magnetorheological Elastomer With and Without Magnetic Field Application

“…MREs are categorized into two types: isotropic MRE, characterized by randomly dispersed particles, and anisotropic MRE, also known as aligned MRE, which undergoes specific curing methods [10]. While investigations have explored particle concentrations in MREs as high as 90 wt.%, most researchers opt for 70 wt.% as it yields optimal MR performance.…”

“…Recognizing shortcomings in conventional curing devices, Khairi et al [10] conducted research to enhance the alignment capability of such devices. Additionally, as noted by Tian et al [15] and Samal et al [16], simulations indicated a minimum magnetic flux density of 0.3 T is required to align particles within the matrix phase.…”