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The friction and wear properties of four different types of magneto-rheological (MR) elastomer were investigated. The MR elastomers have different matrix materials and structures. Most MR elastomers have a silicone matrix, since it has a more significant MR effect under a magnetic field compared to other materials. The mechanical properties of silicone, however, are poor compared to other materials, so it is difficult to use them in engineering applications. Therefore, a new polyurethane matrix material was used to enhance the friction and wear properties of MR elastomer. Additionally, two different matrix materials (silicone and polyurethane) were synthesized, and MR elastomers were structurally combined to improve the friction and wear performance. The friction characteristics of each MR elastomer were evaluated under reciprocating operating conditions. Wear depth was also measured to estimate the wear resistance. The test results show that the friction and wear performance of the modified MR elastomers are enhanced compared with the silicone-based MR elastomer.

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In this study, the magnetic fatigue properties of a magnetorheological elastomer were evaluated with and without a magnetic field. To accomplish the process, a magnetic fatigue tester and magnetorheological elastomer samples were designed and fabricated. The mechanical properties of the magnetorheological elastomer were determined under various fatigue cycle numbers and fatigue frequencies with and without a magnetic field. The shear modulus of the magnetorheological elastomer was also measured before and after the test to evaluate its mechanical properties. The results show that the shear modulus of the magnetorheological elastomer was larger in the presence of a magnetic field and decreased as the number of fatigue cycles increased because the internal structure became loose. Scanning electron microscopy images showed that the internal structure of the magnetorheological elastomer was loose under repeated application of magnetic fields.

This study investigated the stick-slip characteristics of a magneto-rheological elastomer (MRE) against an aluminum plate. Herein, the MRE was manufactured, and a stick-slip tester was employed to evaluate the stick-slip performance of the MRE under different velocities and load conditions with and without a magnetic field. The fast Fourier transform (FFT) of the friction force of the stick-slip and the roughness of the aluminum plate surface were calculated to confirm the stick-slip phenomenon. After the tests, the wear surfaces were observed to evaluate the wear properties of the MRE regarding the stick-slip. Results showed that the stick-slip was smaller at lower velocity. At higher velocity, the reduction of the stick-slip under a magnetic field was more clearly observed. Moreover, the wear reduced with reduced stick-slip under a magnetic field.

Although cutting flow peanut-picking is the main peanut harvesting method, it has the problems of a large harvest loss and a high damage rate of peanut shells. The analysis of impact-friction contact characteristics during peanut fruit picking is crucial to illustrate peanut fruit picking damage. A typical peanut variety, “Dabaisha”, was considered in this study. The characteristics of peanut-picking impact-friction were studied using a peanut-picking impact-friction test bench under different conditions. An orthogonal test with three factors and levels was performed after the single-factor condition was determined. The apparent morphologies of peanut shells before and after the collision and friction tests were compared and analyzed using micro-computed tomography, white-light interferometry, and optical microscopy, whereas the impact-friction damage characteristics of peanuts under the influence of various factors were discussed. The results show that the orders of influence of the coefficient of friction of peanuts and wear loss of peanut pods were as follows: invasion depth > moisture content > contact linear velocity and moisture content > invasion depth > contact linear velocity, respectively. The experimental results and discussion in this study can provide a data reference for developing and designing peanut mechanization production equipment.

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.