# Performance Analysis of Magnetorheological Porous Fabric Composite
###### Abstract  
In this paper, magnetorheological (MR) porous fabric composites were prepared by using non-woven fabrics pretreated with lithium stearate. Due to the porous structure of non-woven fabric and the good stability of lithium stearate, the mechanical properties and sedimentation stability of the composite have been improved. The viscosity, shear stress and dynamic viscoelasticity of different samples were analyzed by rheological properties tests. The results indicate that the mechanical properties of the composite samples containing lithium stearate are improved compared with the MRF (magnetroheological fluid) sample, and its sedimentation stability under non-working conditions is also improved. However, with the increase of lithium stearate content, the improving effect of material performance gradually decreased. The experimental results show that when the magnetic flux density is 0.31 T, the shear stress of the MR porous fabric composite with 1 wt% lithium stearate is about 27 kPa, which increases by 51.1% compared with the MRF sample. magnetorheological fluid; rheological properties; composite; pretreatment +
Footnote †: journal: Applied Sciences  
of the modified carbonyl iron powder composites is smaller than that of the conventional composite. [PERSON] et al. [27] manufactured an MRF-augmented fabric to enhance the ballistic performance of fragment barrier materials. The experimental results demonstrated that the composite has a good ability to absorb impact energy. Based on the above-mentioned, there are numerous studies on preparation, development and application of MR composites; only a few articles reported the aspect of using MRF with porous structures. The porous structure has a better effect on the mechanical properties of composites [28]. Presently, the most widely used fabrics are woven from aramid and ultrahigh molecular weight polyethylene (UHMWPE) fibers. For example, [PERSON] et al. [29] prepared and tested three-dimensional spacer fabric with MRF to improve the stiffness of the material. Moreover, the stiffness of the composite excited by the magnetic field is significantly improved at ambient temperature. With the increase in temperature, the stiffness decreases, but the thermal conductivity increases. [PERSON] et al. [30] presented the preparation and test of three types of composites, including MR fabric composites, magnetic elastomers and MR sponge composites, in order to determine the possible rigidification properties of the magnetic and MR materials. The results illustrate that the magnetic particles or MR components in the composite samples have a great influence on the performance of the device, and the properties are related to the content of magnetic particles and the surface state. Non-woven fabric is a new kind of MR carrier substrate, which has the capability of preventing leakage of the MRF in the rotary devices and effectively enhances mechanic performances and sedimentation stability of MRF [31]. [PERSON] et al. [32] developed a small-scale seismic linear MR damper by using the MRF porous composite made of non-woven porous materials impregnated with MRF to prevent sedimentation of magnetic particles. The results show that the damping force of the designed damper can reach 20 kN at the applied current of 0.5 A. [PERSON] et al. [33] proposed a vibration absorber based on a variable inertia flywheel by employing MRF stored in non-woven fabric, where experimental results are in good agreement with the simulation. Moreover, the inertia adjustment range of the proposed inertia flywheel can reach 27.2%. Although non-woven fabrics with MRF have been widely researched and explored, most literature focuses on applications based on non-woven fabrics and lacks analysis of some factors affecting their mechanical properties. Thus, the main work of the paper is to investigate the effect of pretreatment on output mechanical performance of non-woven fabric.