Experimental Study on Rolling Friction Coefficient Controllability of Magnetorheological Elastomer

2021 ◽  
Vol 143 (12) ◽  
Author(s):  
Chenglong Lian ◽  
Kwang-Hee Lee ◽  
Chul-Hee Lee ◽  
Yongfeng Li ◽  
Peng Zhang
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Friction Coefficient ◽  
Smart Materials ◽  
Slip Rate ◽  
Rolling Friction ◽  
Slip Rates ◽  
Stiffness Control ◽  
Rolling Friction Coefficient ◽  
Field Strengths

Abstract Magnetorheological elastomers (MREs) are smart materials whose stiffness and shear modulus can be changed by applying an external magnetic field. They can be used in various ways. This experimental study looks at the rolling friction coefficient controllability of MREs. MRE samples were manufactured, and their rolling friction properties were measured by a rolling friction test, in which the input magnetic field strengths and rolling speed can be adjusted. Various speed conditions were applied to find the rolling friction properties under different applied magnetic field strengths. The rolling friction coefficient and slip rate control under a magnetic control were then analyzed. The results show that the rolling friction coefficient can be adjusted at different rolling slip rates by the application of a magnetic field, which can increase the rolling friction coefficient range in the control system of the rolling friction coefficient and slip rate. Based on the results of this research, MREs could someday be used in antilock brake systems as a stiffness-control material when a controlled magnetic field is applied, and the rolling friction efficiency could be increased.

Application Study of Magnetorheological Elastomer to Rolling Friction Control

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Chenglong Lian ◽  
Kwang-Hee Lee ◽  
Chul-Hee Lee
Keyword(s):  
Magnetic Field ◽  
Friction Coefficient ◽  
Smart Materials ◽  
Slip Rate ◽  
Rolling Friction ◽  
Friction Property ◽  
Application Study ◽  
Magnetorheological Elastomers ◽  
Friction Control ◽  
Rolling Friction Coefficient

Magnetorheological elastomers (MREs) are smart materials that have been studied widely for their material properties. The elasticity modulus or hardness of an MRE can be changed when an external magnetic field is applied. In this study, a study of MREs applied to rolling friction control under various external magnetic strengths is conducted. To accomplish this, the rolling friction property of an elastomer on a rigid plate is analyzed. Then, MREs are prepared, and a rolling friction tester is designed to evaluate the changes in the rolling friction coefficient. The results show that the rolling friction coefficient can be changed with different magnetic field strengths. The rolling friction coefficient of the MRE can be controlled by the applied magnetic field, which can be applied to control the slip rate and be adapted to achieve the optimal friction effect in the future.

scholarly journals Research on the Mechanical Efficiency of High-Speed 2D Piston Pumps

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 853 ◽  
Author(s):  
Yu Huang ◽  
Jian Ruan ◽  
Chenchen Zhang ◽  
Chuan Ding ◽  
Sheng Li
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
High Pressures ◽  
Weight Ratio ◽  
Rolling Friction ◽  
Mechanical Efficiency ◽  
Load Pressure ◽  
Axial Piston Pumps ◽  
Series Of Experiments ◽  
Rolling Friction Coefficient

Since many studies on axial piston pumps aim at enhancing their high power-weight ratio, many researchers have focused on the generated mechanical losses by the three friction pairs in such pumps and attempted to diminish them through abundant and new structural designs of the pump’s components. In this paper, a high-speed 2D piston pump is introduced and its architecture is specifically described. Afterward, a mathematical model is established to study the pump’s mechanical efficiency, including the mechanical losses caused by the viscosity and stirring oil. Additionally, in this study the influences of the rotational speed, the different load pressures, and the rolling friction coefficient between the cone roller and the guiding rail are considered and discussed. By building a test rig, a series of experiments were carried out to prove that the mechanical efficiency was accurately predicted by this model at low load pressures. However, there was an increasing difference between the test results and the analytical outcomes at high pressures. Nevertheless, it is still reasonable to conclude that the rolling friction coefficient changes as the load pressure increases, which leads to a major decrease in the mechanical efficiency in experiments.

Study of Microwave Reflection Behaviour in Fe3O4 Magnetorheological Fluids

2011 ◽  
Vol 287-290 ◽  
pp. 2785-2788
Author(s):  
Nan Hui Yu ◽  
Ji Jun Fan
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
External Magnetic Field ◽  
Field Strength ◽  
Smart Materials ◽  
Particle Concentration ◽  
Critical Concentration ◽  
Microwave Frequency ◽  
Magnetorheological Fluids ◽  
Microwave Reflection

Owing to its unique properties and wide engineering applications, magnetorheological fluids (MRF) has become a hot study area in the field of smart materials. In this paper experimental study of the microwave reflection behavior in MRF was carried out. The results indicated that at the same frequency the microwave reflectivity of MRF decreased with the increasing of magnetic field strength; and with the particle concentration increasing, microwave reflectivity first increased, then decreased, there is a critical concentration of 15%. Under the same magnetic field, with the increasing of microwave frequency, it first decreased, there is a lowest point at 9.2GHz, and then it increased. Usually, it is considered that the change of internal structure of MRF under external magnetic field is the main reason for the regulation behavior of microwave reflectivity.

scholarly journals Influence of Rolling Friction Coefficient on Inter-Particle Percolation in a Packed Bed by Discrete Element Method

2016 ◽  
Vol 61 (4) ◽  
pp. 1795-1804
Author(s):  
Heng Zhou ◽  
Zhiguo Luo ◽  
Tao Zhang ◽  
Yang You ◽  
Haifeng Li ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Discrete Element Method ◽  
Dispersion Coefficient ◽  
Packed Bed ◽  
Discrete Element ◽  
Rolling Friction ◽  
Size Ratio ◽  
Longitudinal Dispersion ◽  
Longitudinal Dispersion Coefficient ◽  
Rolling Friction Coefficient

Abstract Rolling friction representing the energy dissipation mechanism with the elastic deformation at the contact point could act directly on particle percolation. The present investigation intends to elucidate the influence of rolling friction coefficient on inter-particle percolation in a packed bed by discrete element method (DEM). The results show that the vertical velocity of percolating particles decreases with increasing the rolling friction coefficient. With the increase of rolling friction coefficient, the transverse dispersion coefficient decreases, but the longitudinal dispersion coefficient increases. Packing height has a limited effect on the transverse and longitudinal dispersion coefficient. In addition, with the increase of size ratio of bed particles to percolation ones, the percolation velocity increases. The transverse dispersion coefficient increases with the size ratio before D/d<14. And it would keep constant when the size ratio is greater than 14. The longitudinal dispersion coefficient decreases when the size ratio increases up to D/d=14, then increases with the increase of the size ratio. External forces affect the percolation behaviours. Increasing the magnitude of the upward force (e.g. from a gas stream) reduces the percolation velocity, and decreases the dispersion coefficient.

scholarly journals Pre-service teachers’ conceptual understanding of rolling friction coefficient

2018 ◽  
Author(s):  
Puspita Septim Wulandari ◽  
C. Cari ◽  
Nonoh Siti Aminah ◽  
Dewanta Arya Nugraha
Keyword(s):  
Friction Coefficient ◽  
Conceptual Understanding ◽  
Rolling Friction ◽  
Rolling Friction Coefficient

Discrete Element Modeling of Seed Metering as Affected by Roller Speed and Damping Coefficient

2020 ◽  
Vol 63 (1) ◽  
pp. 189-198
Author(s):  
Leno J. Guzman ◽  
Ying Chen ◽  
Hubert Landry
Keyword(s):  
Friction Coefficient ◽  
Mass Flow ◽  
Discrete Element ◽  
Rolling Friction ◽  
Angle Of Repose ◽  
Discrete Element Modeling ◽  
Flow Rates ◽  
Damping Coefficients ◽  
Mass Flow Rates ◽  
Rolling Friction Coefficient

Abstract. The development of highly efficient seed metering is required to meet the demands of modern seeding equipment. The discrete element method (DEM) was used to simulate metering of seeds with a fluted roller meter. This approach was chosen due to its capability to accurately represent granular material flow. The contact model selected for the DEM simulation was the linear rolling resistance model. Angle of repose experimental tests and simulations were performed to calibrate the rolling friction coefficient for peas. The calibrated value for the rolling friction coefficient was 0.016. A 192 mm cross-section of an air cart seed roller and housing was defined as the domain of the simulation. Sensitivity analysis showed that simulated mass flow rates were not sensitive to the selected damping coefficients (0.2, 0.5, and 0.8). Sensitivity indicator values varied between -0.049 and 0.088 for the range of damping coefficients and roller speeds studied. The simulated geometry of the seed meter and housing resulted in a steady flow of seeds, with discharged mass increasing linearly. The simulated mass flow rates were 34.0, 72.3, 110.4, 147.3, and 182.0 g s-1 for roller speeds of 10, 20, 30, 40, and 50 rpm, respectively. An experiment was performed to validate the simulation results. The predicted mass flow rate values of the simulation were within 10 g s-1 of the experimental results, with the largest relative error being 16.5%. Keywords: DEM, Damping, Metering, Peas, Rolling friction coefficient, Seed, Simulation.

Influence of Shape and Particle Size Distribution on Discrete Element Simulation Flow Characteristics of Granular Compound Fertilizers

2021 ◽  
Vol 37 (6) ◽  
pp. 1169-1179
Author(s):  
Wenli Xiao ◽  
Hui Chen ◽  
Xingyu Wan ◽  
Mengliang Li ◽  
Qingxi Liao
Keyword(s):  
Particle Size ◽  
Friction Coefficient ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Golden Section ◽  
Discrete Element ◽  
Rolling Friction ◽  
Angle Of Repose ◽  
Compound Fertilizer ◽  
Rolling Friction Coefficient

HighlightsThe relationship between the angle of repose and compound fertilizer particle size distribution and sphericity was revealed.The range of the rolling friction coefficient obtained by different modeling was calibrated by the golden section method.Scanning modeling required 80% of the rolling friction coefficient of spherical modeling to reflect actual motion.The relative error of scanning modeling (7.91%) was better than that of spherical modeling (30.84%).Abstract. The discrete element method (DEM) is widely used to simulate the behavior of granular materials. The accurate establishment of the particle model has a great influence on the accuracy of the simulation. Most of the existing discrete element simulations of granular compound fertilizers use spherical modeling without considering the shape or particle size distribution. To compare the simulation accuracy of spherical modeling (spherical particles with equivalent diameters) and scanning modeling (a three-dimensional model of fertilizers was obtained by a scanner and then automatically filled by EDEM2020 software) on compound fertilizer discharge, three kinds of granular compound fertilizers (Changqingshu, Xinshidai, and Munvhong) were selected as the research objects. The characterization parameters of fertilizer shape and fluidity were measured. Principal component analysis and Pearson correlation analysis were used to analyze the influence of the compound fertilizer characterization parameters on the angle of repose. The results showed that the particle shape and particle size distribution of compound fertilizer were the main factors affecting its angle of repose. Through the golden section method and a single-factor experiment, the rolling friction coefficients of the three granular fertilizers under the two granular modeling methods for spherical modeling and scanning modeling were determined. The results showed that the rolling friction coefficient when using scanning modeling to approximate the actual angle of repose was approximately 80% of that when using the spherical modeling method. The influence of different modeling methods on the total rotational kinetic energy and the formation of the angle of repose was discussed. For the same fertilizer, the total rotational kinetic energy was greater in spherical modeling than in scanning modeling, and the formation time of the angle of repose was longer in scanning modeling than in spherical modeling. The results of an external tank wheel fertilization simulation and bench test showed that considering the scanning modeling of fertilizer shape and particle size distribution, the fertilization variation coefficient obtained from the simulation test was closer to that of the bench test. This research helps to better understand the influence of particle shape and particle size distribution on DEM simulations and provides references for discrete element modeling of other granular fertilizers. Keywords: Compound fertilizer, Modeling method, Shape, Simulated flow characteristics, Size distribution.

Calibration and Experimental Validation of Contact Parameters for Oat Seeds for Discrete Element Method Simulations

2021 ◽  
Vol 37 (4) ◽  
pp. 605-614
Author(s):  
Lingxin Geng ◽  
Jiewen Zuo ◽  
Fuyun Lu ◽  
Xin Jin ◽  
Chenglong Sun ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Discrete Element Method ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Angle Of Repose ◽  
Static Friction Coefficient ◽  
Contact Parameters ◽  
Rolling Friction Coefficient ◽  
Element Method

Highlights The static friction coefficient and rolling friction coefficient of oat seeds were calibrated by the discrete element method. Two representative oat varieties were selected. The hollow cylinder method and sidewall collapse method were used together to reduce the test error. Abstract . Hulless and shelled oat are two types of oat with major differences in physical appearance. To study the contact parameters between the two different oat seed types, these parameters were delineated with the discrete element method and graphic image processing technology. Using plexiglass as the contact material, the experiments used two different angle of repose measurement methods—hollow cylinder and collapse sidewall devices, to perform bench and simulation experiments on the two different oats. Under different measurement methods, bench experiments measured the angles of repose of the two oat seed types at 33.19°, 33.82° and 22.45°, 23.57°; the static friction coefficient and rolling friction coefficient were the experimental factors, and the angle of repose was the experimental indicator in the simulation. The steepest climbing experiment determined the optimal range of the experimental factor, and the regression equation between the static friction coefficient, rolling friction coefficient and angle of repose was established by a quadratic orthogonal rotation combination experiment. Finally, the angles of repose measured by the bench experiment with the two different measurement methods were treated as target values, the coefficient of static friction and the coefficient of rolling friction were solved; the coefficient of static friction between hulless oats was 0.36, and the coefficient of rolling friction between hulless oats was 0.052; the coefficient of static friction between shelled oats was 0.24, and the coefficient of rolling friction between shelled oats was 0.036. The obtained contact parameters between seeds were input into EDEM, the simulation and bench experiment results were verified. The difference between the simulation results and the actual values was within 3%. The angle of repose of oats after calibration was close to the actual situation, and the calibration results had high reliability and provided a referencefor the measurement of contact parameters between other agricultural crop seeds. Keywords: Calibration, Contact parameters, Discrete element method, Oat.

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