Experimental Study For The Effect Of Initial Surface Roughness On Tribological Characteristics Of MR Fluid

Magneto-rheological(MR)fluid is a king of classical smart material that consists of stable suspensions of microsized magnetically polarizable particles,carrier liquid,and stabilizing additives.The MR fluid whose particles are polarized and lined along the magnetic field produce the obvious MR effect under the action of an external magnetic field.MR fluid instantaneously changes from a free-flowing liquid to a semi-solid with the change of the magnetic field intensity.This reversible and controllable transformation provides a broad application prospects for the development of MR fluid,such as aerospace,automotive industry,mechanical engineering,construction,and health care.The working principle of MR fluid is utilizing the instantaneous change of the shear stress on the surface to achieve the control effect under external magnetic field.Therefore,the tribological characteristics of MR fluid are crucial to the control performance of MR fluid.In addition,MR damper and other related products mainly adopt the sealing elements to seal the MR fluid in structural design.However,the sealing element is easy to be worn in the working process.Based on a series of problems about the application of MR fluid,this paper will focus on the friction and wear characteristics of the MR fluid on different initial surface roughness under magnetic field and analyze the tribological behavior and wear mechanism.The paper has researched some works as bellows:First of all,the MR generating device that is designed by combining with existing equipment in the laboratory generates the larger magnetic field during friction process,which makes the MR fluid better exert its rheological properties.Secondly,the simulation analysis on magnetic field for the MR generating device is carried out by using finite element analysis software in order to ensure that the magnetic field generated meets the test requirements.The magnetic inductions produced by the MR generating device are measured by a gaussmeter under different currents to prove the accuracy of simulated results.Again,the friction and wear characteristics of the MR fluid on different initial surface roughness under magnetic field are investigated through carrying out the wear tests and analyzing the experiment results.Finally,the microstructures of the worn surface of specimens are observed by scanning electron microscope(SEM).From the SEM micrographs,the tribological behavior and wear mechanism on the worn surface of specimens are further studied in this paper.