Test And Reaserch On Magnetic Property Of Magnetorheological Material

Magnetorheological material is a kind of intelligent material that can sense and judge the external magnetic field and then change its physicochemical properties.As the intrinsic property of magnetorheological material,magnetic conductivity is the key factor to optimize and decide the structure of the vibration isolator based on magnetorheological materials,but there is little literature on its research.Relative permeability is an important parameter to characterize the magnetic conductivity of magnetorheological materials.Through the measurement and study of relative permeability,the magnetic conductivity of magnetorheological materials can be further mastered.In the paper,a device to measure relative permeability of magnetorheological material is constructed based on indirect measurement.The device can not only measure the relative permeability of magnetorheological elastomer,but also measure the magnetorheological material with fluidity such as magnetorheological glue.The device has a certain universality,which is conducive to the testing and research on the magnetic conductivity of magnetorheological material and provides the basic conditions for expanding the application of magnetorheological material in the field of ship vibration control.This article mainly carried out the following work:(1)Preparation of polyurethane magnetorheological elastomer.The preparation scheme of the polyurethane magnetorheological elastomer is determined by selecting the components,designing the preparation process and calculating the amount of the components.According to the preparation of polyurethane magnetorheological elastomer,the polyurethane magnetorheological elastomer with different components and proportions is prepared,providing the experimental basis for the study.(2)Design and construction of magnetic conductivity measuring device.Firstly,a mold is designed to measure the relative permeability of magnetorheological material based on the principle of indirect measurement,which can also be used to test the mechanical properties of magnetorheological elastomer.Secondly,using the JMAG software to simulate the magnetic field distribution in the mold and the magnetic field in the test area,and then using the Tesla meter to calibrate the mold test area.The measured current magnetic field is compared withthe simulation results,the results show that the mold has excellent consistency.Finally,the magnetic permeability measuring device is built.(3)Measurement and optimization of magnetic conductivity of polyurethane magnetorheological elastomer.Firstly,the relative permeability of magnetorheological elastomer is tested based on frequency method,the results show that the MRE prepared in this study can be used for the subsequent testing of magnetic conductivity.Secondly,the factors affecting the relative permeability of polyurethane MRE are measured respectively.The results show that the relative permeability of polyurethane MRE increases with the concentration increase of magnetic particles,additives and plasticizer,and decreases with the increase of magnetic field.The decreasing trend gradually diminishs with the weakening trend of magnetic field accelerated.The molar ratio of polyurethane matrix material had little effect on the relative permeability,and the polyurethane magnetorheological elastomer prepared under the pre-applied magnetic field had a higher density than the non-pre-applied magnetic field.Finally,the permeability of polyurethane MRE is analyzed,and the magnetic permeability is optimized by two methods,that is magnetic particle modification and matrix modification.(4)Measurement of relative permeability of magnetorheological fluids and magnetorheological glue.Firstly,in order to measure a magnetorheological material such as magnetorheological fluid which has fluidity,a simple package was developed and its feasibility verified.Secondly,the relative permeability of magnetorheological fluid and magnetorheological glue was measured respectively by the modified magnetic permeability measuring device.And then research the result,the results show that the magnetic permeability and magnetorheological fluids can be measured by the magnetic permeability measuring device.