Research On Rolling Friction Characteristics Of Magnetorheological Elastomers Controlled By Magnetic Field

The rolling friction coefficient between internal components of large-scale mechanical equipment and system will be decreased under the long-term operation.Especially in a wet environment,the rolling friction coefficient will cause the device to slip,resulting in instability or failure of the system,causing unpredictable losses to the people and society.Aiming at the problem of system stability reduction caused by rolling friction reduction,it is found that the magnetic friction under the action of magnetic filed.By adjusting the rolling friction of magnetorheological elastomers by controlling the magnetic induction,the rolling friction coefficient in wet and slippery environment can be increased,which ensures that the mechanical system works normally.However,the experimental and theoretical research on the rolling friction characteristics of magnetorheological elastomers is not perfect.Therefore,the rolling friction characteristics of magnetorheological elastomers are studied from two perspectives by combining the experimental and theoretical research methods,which provides technical support for the engineering application of the controllable rolling friction of magnetorheological elastomers.The specific contents of this paper are as follow:1.The background and significance of the research on rolling friction characteristics of magnetorheological elastomers are expounded.The magnetic properties of magnetorheological elastomers and rolling friction measurement technology are analyzed.The existing problems in the research of magnetically controlled rolling friction of magnetorheological elastomers are pointed out.The solutions are put forward and the main research contents of this paper are introduced.2.In view of the imperfect research of magnetorheological elastomers' rolling friction experiment,according to the requirements of the experimental system,the speed control device,magnetic field control module and information processing module were designed and the experimental system was built.In addition,in order to solve the problem of single material for rolling friction research of magnetorheological elastomers,isotropic and anisotropic magnetorheological elastomers with different volume ratios of ferromagnetic particles were prepared,which lays a foundation for the subsequent experimental study of the magnetorheological elastomers' rolling friction.3.In view of the lack of research on rolling friction of magnetorheological elastomers under wet and slippery environment,experimental research methods of rolling friction with controllable magnetic field,adjustable speed,variable load and variable surface of magnetorheological elastomers were proposed.The experimental conditions include magnetic induction strength of 0mT,50 mT,100mT and 150 mT,and velocity of 0.2m/s?2.3m/s,and three different paired(glass ball,ceramic ball,copper ball),and four different magnetorheological elastomers' surfaces(drying,water attachment,vegetable oil and oil surface).It was found that the rolling friction effect of ferromagnetic particles 10% isotropic and 3% anisotropic magnetorheological elastomers was the best when paired with different fiction pairs.Under the condition of velocity 1.5m/s and magnetic induction strength 150 mT,the friction coefficient of 10% isotropic magnetorheological elastomers increases by 38% from 0.0045 to 0.0062,and that of 3% anisotropic magnetorheological elastomers increases by 29% from 0.0051 to 0.0066.In addition,under the same conditions,the rolling friction coefficient of 10% isotropic magnetorheological elastomers on the water-adhered surface decreases from 0.0045 to 0.0034,which is increased to 0.0059 under the magnetic field,and the lift is about 55%.The rolling friction coefficient on the vegetable oil surface decreases from 0.0045 to 0.0021,which is increased to 0.0041 under the magnetic field,and the lift is about 44%.The rolling friction coefficient on the oil surface decreases from 0.0045 to 0.0032,which is increased to 0.0041 under the magnetic field,and the lift is about 20%.It provides data support for the research of rolling friction of magnetorheological elastomers.4.In view of the lack of theoretical research on rolling friction of magnetorheological elastomers,in order to analyze the influencing factors of rolling friction coefficient,the magnetic induction intensity,rolling speed and load are demonstrated.Considering magnetorheological elastomers as linear elastic material,magnetic field leads to the increase of its Young's modulus.Based on semi-empirical method,a rolling model of magnetorheological elastomers is established.It is concluded that the magnetic field is increased,and the Young's modulus of the magnetorheological elastomers is increased,and its rolling friction coefficient is increased.Furthermore,the model based on the elastic hysteresis effect shows that the rolling fiction coefficient is proportional to the speed and inversely proportional to the load,which provides a theoretical basis for the engineering application of magnetorheological elastomers.