Study on sliding friction characteristics of magnetorheological elastomer - copper pair affected by magnetic-controlled surface roughness and elastic modulus

Abstract To optimize the online friction coefficient adjustment, it is necessary to study the parameter change features of the magneto-sensitive polymer and its influence on the friction characteristics under magnetic field. A series of magnetorheological elastomers (MREs) with different initial surface roughness were prepared, and a sliding friction platform with MRE - copper block pair was built to carry out magnetic-controlled friction characteristic experiment. Results show that the sliding friction coefficient of MRE decreases with the increase of the magnetic field, but the degree of reduction is quite different under different initial surface roughness and elastic modulus. When the initial surface roughness of MRE is between 0.5 - 2.5 μm and the carbonyl iron particles (CIPs) volume fraction is between 10% - 15%, its magnetic-controlled friction coefficient has the largest reduced value of 22.75%. Moreover, features of elastic modulus and surface topography under magnetic field were tested and analyzed. By combining with the single peak contact model and the friction binomial law, the relationship between the surface roughness and elastic modulus of MREs and the sliding friction force is deduced, and it is proved that the friction coefficient is affected by the coupling effect of surface roughness and elastic modulus. The magnetic-controlled elastic modulus is the key factor, which determines the overall downward trend of the friction coefficient of MREs. Magnetic-controlled surface roughness also plays an important role in the adjustable range of friction coefficient, and reducing the initial surface roughness can increase the magnetic-controlled friction coefficient adjustable range.

Download Full-text

Study on Sliding Friction Characteristics of Magnetorheological Elastomer - Copper Pair Affected by Magnetic-Controlled Surface Roughness and Elastic Modulus

10.21203/rs.3.rs-146108/v1 ◽

2021 ◽

Author(s):

Rui Li ◽

Di Wang ◽

Xinyan Li ◽

Ping-an Yang ◽

Haibo Ruan ◽

...

Keyword(s):

Magnetic Field ◽

Surface Roughness ◽

Elastic Modulus ◽

Friction Coefficient ◽

Sliding Friction ◽

Volume Fraction ◽

Coupling Effect ◽

Initial Surface ◽

Friction Characteristics ◽

Adjustable Range

Abstract To optimize the online friction coefficient adjustment, it is necessary to study the parameter change features of the magneto-sensitive polymer and its influence on the friction characteristics under magnetic field. A series of isotropic magnetorheological elastomers (MREs) with different initial surface roughness were prepared, and a sliding friction platform with MRE - copper block pair was built to carry out magnetic-controlled friction characteristic experiment. Results show that the sliding friction coefficient of MRE decreases with the increase of the magnetic field, but the degree of reduction is quite different under different initial surface roughness and elastic modulus. When the initial surface roughness of MRE is between 0.5 - 2.5 μm and the ferromagnetic particles volume fraction is between 10% - 15%, its magnetic-controlled friction coefficient has the largest reduced value of 22.75%. Moreover, features of elastic modulus and surface topography under magnetic field were tested and analyzed. By combining with the single peak contact model and the friction binomial law, the relationship between the surface roughness and elastic modulus of MREs and the sliding friction force is deduced, and it is proved that the friction coefficient is affected by the coupling effect of surface roughness and elastic modulus. The magnetic-controlled elastic modulus is the key factor, which determines the overall downward trend of the friction coefficient of MREs. Magnetic-controlled surface roughness also plays an important role in the adjustable range of friction coefficient, and reducing the initial surface roughness can increase the magnetic-controlled friction coefficient adjustable range.

Download Full-text

Surface Characterization and Tribological Performance of Anodizing Micro-Textured Aluminum-Silicon Alloys

Materials ◽

10.3390/ma12111862 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1862 ◽

Cited By ~ 2

Author(s):

Luanxia Chen ◽

Zhanqiang Liu ◽

Bing Wang ◽

Qinghua Song ◽

Yi Wan ◽

...

Keyword(s):

Surface Roughness ◽

Friction Coefficient ◽

Sliding Friction ◽

Tribological Performance ◽

Area Ratio ◽

Micro Milling ◽

Dry Sliding ◽

Silicon Alloys ◽

Aluminum Silicon Alloys ◽

Aluminum Silicon

Eutectic aluminum-silicon alloys present high frictional coefficient and a high wear rate due to the low hardness under sliding friction conditions. In this paper, the eutectic aluminum-silicon alloy was textured firstly by micro-milling operations. Then, the micro-textured specimen was subjected to anodizing to fabricate alumina films. The surface topography, surface roughness, and bearing area ratio of micro-textured and anodizing micro-textured specimens were measured and characterized. For the anodizing micro-textured specimens, the surface roughness and superficial hardness increase compared with those for micro-textured ones. Tribological tests indicate that anodizing micro-textured samples present lower friction coefficient of 0.37 than that of flat samples of 0.43 under dry sliding conditions. However, they exhibit higher friction coefficient at 0.16 than that of flat samples of 0.13 under oil-lubricated conditions. The difference between the friction coefficient of anodizing micro-textured and flat samples under dry and oil-lubricated conditions is ascribed to the influence mechanism of surface roughness, bearing area ratio curves, and its relative parameters on the tribological performance of testing samples. The dry sliding friction coefficient has a positive correlation with bearing area ratio curves, while they present negative correlation with bearing area ratio curves under oil-lubricated conditions. The synergy method treated with micro-milling and anodizing provides an effective approach to enhance the dry sliding friction property of eutectic aluminum-silicon alloys.

Download Full-text

Analysis of Forces During Spot Finishing of Titanium Alloy Using Novel Tool in Magnetic Field Assisted Finishing Process

Volume 4: Processes ◽

10.1115/msec2018-6352 ◽

2018 ◽

Author(s):

Anwesa Barman ◽

Manas Das

Keyword(s):

Magnetic Field ◽

Surface Roughness ◽

Titanium Alloy ◽

Normal Force ◽

Tangential Force ◽

Abrasive Particle ◽

Initial Surface ◽

Precise Control ◽

Percentage Improvement ◽

Finishing Process

Magnetic field assisted finishing process is a nanofinishing process which uses magnetic field for precise control of finishing forces. Magnetorheological fluid mixed with diamond abrasive particles in base medium of glycerol, hydrofluoric acid, nitric acid, and deionized water is used as the polishing medium. The novel tool is a magnet fixture made of mu-metal which is used to hold the magnet during finishing. In the present experimental study, finishing at a spot on flat titanium alloy is carried out to analyze the forces involved in the finishing. Normal force is the main force responsible for the indentation by the abrasive particle on the workpiece surface. Tangential force helps in removing indented material. The measured normal force and tangential force during the spot finishing are 3.285 N and 0.43 N, respectively. The final surface roughness achieved after spot finishing is 10 nm from initial surface roughness of 200 nm. The percentage improvement in surface roughness is 95%.

Download Full-text

Study on Internal Magnetic Field Assisted Finishing Process Using a Magnetic Machining Jig for Thick Non-Ferromagnetic Tube

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.325.530 ◽

2011 ◽

Vol 325 ◽

pp. 530-535 ◽

Cited By ~ 3

Author(s):

Yan Hua Zou ◽

Jiang Nan Liu ◽

Takeo Shinmura

Keyword(s):

Magnetic Field ◽

Surface Roughness ◽

Steel Tube ◽

Machining Process ◽

Surface Finishing ◽

Stainless Steel Tube ◽

Initial Surface ◽

Rough Machining ◽

Form Accuracy ◽

Finishing Process

This paper describes an internal finishing process for thick non-ferromagnetic tube (10~20 mm in thickness) by the application of a magnetic field-assisted machining process using a magnetic machining jig (permanent magnet tool). In this study, a new automatic inner surface finishing system was developed, and to achieve smooth surface roughness and high form accuracy, a multiple-stage machining which contains of rough machining and precision finishing was carried out. Especially, in order to improve the form accuracy the rough processing time was made longer compared with the research in the past. The experiments were performed for a thick SUS304 stainless steel tube 10 mm in thickness. The results showed that surface-roughness and form accuracy were able to be improved greatly, the initial surface roughness of 4.9μmRa can be improved to 0.01 μmRa and the roundness of inside tube can be improved from 206 μm to13μm.

Download Full-text

Martensite Variant Reorientation of NiMnGa/Silicone Composites Containing Polystyrene Foam Particles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.409.645 ◽

2011 ◽

Vol 409 ◽

pp. 645-650 ◽

Cited By ~ 2

Author(s):

Yui Watanabe ◽

Motoki Okuno ◽

Yoshinaka Shimizu ◽

Hiroyasu Kanetaka ◽

Tomonari Inamura ◽

...

Keyword(s):

Magnetic Field ◽

Elastic Modulus ◽

Volume Fraction ◽

Parent Phase ◽

Dominant Factor ◽

Matrix Composites ◽

Zone Method ◽

Martensite Variant ◽

Matrix Polymer ◽

The Magnetic Field

Effect of elastic modulus of matrix on ferromagnetic motion of NiMnGa particles was investigated for NiMnGa particles embedded silicone matrix composites with or without containing polystyrene form particles (PFPs), which are regarded as pores. NiMnGa single crystal was fabricated by a floating zone method and a cube-shape particle was fabricated with the surface orientation parallel to [100], [010] and [001] directions at the parent phase state. The elastic modulus of matrix polymer was controlled by changing the number of PFPs. It was found that the elastic modulus of silicone was decreased with increasing the volume fraction of PFPs. The magnetic-field-induced martensite variant reorientation (MVR) was evaluated by the magnetization curves obtained using a vibration sample magnetometer, and the magnetic field required for the start of martensite variant reorientation was reduced by increasing the number of PFPs. The control of elastic modulus of matrix polymer is important and a dominant factor for the magnetic motion of NiMnGa/polymer composites.

Download Full-text

Magnetic Field Dependent Damping of Magnetic Particle Filled Polypropylene

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.184.449 ◽

2012 ◽

Vol 184 ◽

pp. 449-454

Author(s):

O.A. Lambri ◽

D. Gargicevich ◽

F. Tarditti ◽

F.G. Bonifacich ◽

Werner Riehemann ◽

...

Keyword(s):

Magnetic Field ◽

Elastic Modulus ◽

Internal Friction ◽

Polymer Matrix ◽

Volume Fraction ◽

Alternating Magnetic Field ◽

Internal Stresses ◽

Dynamic Shear Modulus ◽

Dc Magnetic Field ◽

Damaged Zone

The behavior of internal friction Q-1 and dynamic shear modulus has been studied in polypropylene charged with either different volume fraction or size of magnetite (Fe3O4) particles, as a function of the applied magnetic field at 318 K. An increase of the alternating (AC) magnetic field oscillating with 50 Hz, leads to an increase of the internal friction. In addition, during the subsequently decreasing alternating magnetic field, the internal friction decreases, but a hysteretic behavior appeared. In fact, the internal friction of the decreasing part of magnetic field amplitude is found to be smaller than during the previously increasing amplitude part of the treatment with the alternating magnetic field. Subsequent magnetic treatment cycles, lead to successively decreasing internal friction. In contrast, during the increase of a direct (DC) magnetic field, the internal friction decreases and the elastic modulus increases. The behavior of the internal friction and the elastic modulus during the application of an oscillating magnetic field (AC) is discussed on the basis of the development of both, a new zone with different rheological characteristics than the matrix but of the same material (self-inclusion), and/or a deteriorated or damaged zone (chain’s cuts) of the polymer matrix in the neighborhood of the magnetite inclusion. These effects are promoted by the movement or small relative rotation of the magnetite particles related to the surrounding matrix controlled by the oscillating field. The behavior of the internal friction and elastic modulus during the application of a direct (DC) magnetic field is discussed on the basis of the increase of the internal stresses into the polymer matrix due to the promotion of the magnetomechanical stresses.

Download Full-text

The Effect of Grain Size and Shape on Sliding Friction of Wet Granular Media

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2018-1267 ◽

2020 ◽

Vol 234 (1) ◽

pp. 107-116 ◽

Cited By ~ 1

Author(s):

Mojgan Aliasgari ◽

Nahid Maleki-Jirsaraei ◽

Shahin Rouhani

Keyword(s):

Grain Size ◽

Friction Coefficient ◽

Granular Media ◽

Sliding Friction ◽

Volume Fraction ◽

Silicone Oil ◽

Network Effect ◽

Crossover Point ◽

Interstitial Liquid ◽

Capillary Bridges

AbstractThe wet granular material creates networks in which interstitial liquid provides capillary bridges needed to hold grains together. There is an optimal fraction of the interstitial liquid in which the bridges are formed and the friction coefficient is minimal. We found that the size of the grains affects the friction of wet granular media. Our observations demonstrates that the optimum volume fraction, in which the friction coefficient is minimized, increases with grain size, but for sand immersed in water, this minimum friction coefficient itself increases with size and for glass beads immersed in silicone oil it decreases, indicating that the shape of the grains also has an effect on this friction. It is also shown that there is a crossover point for grain size at which the network effect created by capillary bridges is dominated by wet granular media. This crossover point is found.

Download Full-text

Experimental and numerical study on surface roughness of magnetorheological elastomer for controllable friction

Friction ◽

10.1007/s40544-017-0309-0 ◽

2019 ◽

Vol 8 (5) ◽

pp. 917-929 ◽

Cited By ~ 1

Author(s):

Rui Li ◽

Xi Li ◽

Yuanyuan Li ◽

Ping-an Yang ◽

Jiushan Liu

Keyword(s):

Magnetic Field ◽

Surface Roughness ◽

Surface Morphology ◽

Volume Fraction ◽

Particle Volume Fraction ◽

Rubber Matrix ◽

Magnetorheological Elastomer ◽

Particle Volume ◽

Simulation Results ◽

The Magnetic Field

Abstract Magnetorheological elastomer (MRE) is a type of smart material of which mechanical and electrical properties can be reversibly controlled by the magnetic field. In this study, the influence of the magnetic field on the surface roughness of MRE was studied by the microscopic modeling method, and the influence of controllable characteristics of the MRE surface on its friction properties was analyzed by the macroscopic experimental method. First, on the basis of existing studies, an improved mesoscopic model based on magnetomechanical coupling analysis was proposed. The initial surface morphology of MRE was characterized by the W-M fractal function, and the change process of the surface microstructures of MRE, induced by the magnetic interaction between particles, was studied. Then, after analyzing the simulation results, it is found that with the increase in the magnetic field and decrease in the modulus of rubber matrix, the surface of MRE changes more significantly, and the best particle volume fraction is within 7.5%–9%. Furthermore, through experimental observation, it is found that the height of the convex peak on the surface of MRE decreases significantly with the action of the magnetic field, resulting in a reduction in the surface roughness. Consistent with the simulation results, a particle volume fraction of 10% corresponds to a maximum change of 14%. Finally, the macroscopic friction experiment results show that the friction coefficients of MREs with different particle volume fractions all decrease with the decrease in surface roughness under the magnetic field. When the particle volume fraction is 10%, the friction coefficient can decrease by 24.7% under a magnetic field of 400 mT, which is consistent with the trend of surface roughness changes. This shows that the change in surface morphology with the effect of the magnetic field is an important factor in the control of MRE friction properties by magnetic field.

Download Full-text

Numerical investigation of sliding friction behaviour and mechanism of engineering surfaces

Industrial Lubrication and Tribology ◽

10.1108/ilt-03-2018-0117 ◽

2019 ◽

Vol 71 (2) ◽

pp. 205-211 ◽

Cited By ~ 1

Author(s):

Xiaogang Zhang ◽

Yali Zhang

Keyword(s):

Surface Roughness ◽

Friction Coefficient ◽

Sliding Friction ◽

Normal Load ◽

Numerical Results ◽

Operating Conditions ◽

Friction Mechanism ◽

Content Type ◽

Optimal Surface ◽

Friction Behaviour

Purpose This study aims to investigate the sliding friction behaviour and mechanism of engineering surfaces. Design/methodology/approach A new numerical approach is proposed. This approach derives the macroscale friction coefficient from microscale asperity interactions. By applying this approach, the sliding friction behaviour under different operating conditions were investigated in terms of molecular and mechanical components. Findings Numerical results demonstrate an independent relationship between normal load and friction coefficient, which is governed by the saturated plastic ratio. Numerical results also demonstrate that under very small load, an increase in load increases the friction coefficient. In addition, numerical results confirm the existence of optimal surface roughness where the friction coefficient is the lowest. For the surface profiles used in the current calculation, an optimal surface roughness value is obtained as Rq = 0.125 μm. Originality/value This new approach characterizes the deterministic relationship between macroscale friction coefficient and microscale asperity molecular/mechanical interactions. Numerical results facilitate the understanding of sliding friction mechanism.

Download Full-text