The Static and Dynamic Mechanical Properties of Magnetorheological Silly Putty

Abstract

A novel magnetorheological material defined as magnetorheological Silly Putty (MRSP) is prepared by dispersing soft magnetic particles into Silly Putty matrix with shear stiffening property. Static mechanical properties including creep and stress relaxation and dynamic rheological properties of MRSPs are tested by rheometer. The experimental results indicate that the external magnetic field exerts significant influence on the creep and relaxation behaviors. Moreover, the storage modulus of MRSPs increases sharply in response to the external stimuli of increasing angular frequency automatically and can be enhanced by external magnetic field. Besides, temperature plays a key role in shear stiffening and magnetorheological effect of MRSPs. Furthermore, considering the obstruction to the particle chains formation induced by Silly Putty matrix, a nonperforative particle aggregated chains model is proposed. The model curve is in consistency with experimental data, which means it can describe magnetoinduced behavior of MRSPs well.

The Mechanical Properties of a Novel STMR Damper Based on Magnetorheological Silly Putty

“…Furthermore, the higher the content of the CI powder is, the more beneficial it is to the absolute shear stiffening effect of the material. In earlier research [1], for the MRSP 5 sample, under normal temperatures, the absolute modulus change is 0.6145 MPa, which equals to approximately twice the pure shear stiffening matrix MRSP 0, while the relative shear stiffening effect is 1412.64%, which is far less than 77584.21% of the pure shear stiffening matrix MRSP 0. However, under the condition of an external magnetic field, the soft magnetic particles of the CI powder were arranged into chain-like ordered structures along the direction of the magnetic flux line in the interior of the shear stiffening matrix, forming the anisotropic structure.…”

“…In the earlier research, when there was no external magnetic field applied, the soft magnetic particles of CI were evenly dispersed in the Silly Putty matrix to form isotropic viscoelastic materials [1]. From this point, the CI powder was considered as a general particle filling, which played a role in strengthening the matrix material.…”

“…Besides, from the earlier research, in order to compare the shear stiffening degree of the MRSP samples, the absolute shear stiffening effect (ASTe) and relative shear stiffening effect (RSTe) are defined as the index of measurement [1], as shown specifically in the following formula:…”

“…Currently, the research results indicated that the lower the loading frequency was, the higher the magnetorheological effect became, and the more the conducive it was to the adjustment of the magnetic field. However, the loading frequency was higher, the matrix modulus of MRSP became larger, the chain-like resistance of soft magnetic particles in the interior of the matrix became greater, and the magnetorheological effect tended to be lower [1]. Figure 6 reveals the varied relationship between the shear storage modulus and magnetic flux density of different samples under the conditions of different shear strain, low load frequency (ω �1 rad/s), and magnetic flux density continuous changing from 0 to 0.894 T. Correspondingly, the larger the shear strain is, the smaller the storage modulus of the sample becomes.…”

“…Magnetorheological Silly Putty (MRSP) is a smart multifunctional composite prepared by dispersing soft magnetic particles into a Silly Putty matrix with shear stiffening property [1]. is new kind of smart material is the solid state of the magnetorheological shear thickening fluid (MRSTF) proposed by Zhang et al and Peng et al [2,3].…”