Study On Stress Field Of Bearing Insulation Coating Under Thermal-Mechanical Coupling

With the rise of the rail transport industry,the phenomenon of galvanic corrosion failure in bearings used in traction motors of rolling stock is gradually attracting attention.The most widely used protection method is to spray a ceramic coating on the outer ring of the bearing to improve the insulation of the bearing,but due to the longterm high temperature and heavy load service environment of the bearing,the insulation coating of the outer ring is prone to cracking and even peeling off.In this paper,the analysis method of finite element simulation is used to study the influence of different factors on the stress distribution in the insulation coating through ANSYS Workbench simulation software,so as to reveal the evolution of the stress field of the insulation coating with the change of different factors.The specific work of this paper is as follows.(1)The main factors affecting the stress distribution in insulating coatings are profiled.In order to study the influence of temperature and load on the stress distribution in insulating coatings,a corresponding theoretical model is established to obtain the changes in the residual stress in coatings under the state of temperature rise,as well as the changes in stress in coatings with different moduli of elasticity under the action of external load.(2)Thermal coupling simulation analysis of insulating coatings was carried out in ANSYS Workbench to study the influence of material structure and environmental factors of insulating coatings on the stress distribution in the coatings,to establish coating models of different structures,thicknesses and materials,and to obtain the changes of stress fields in insulating coatings under different radial loading.(3)To study the effect of impact loading on the insulation coating,transient dynamics analysis was carried out in the dynamics module of ANSYS Workbench,and ADAMS was used to determine a short period of instability during the cyclic operation of the bearing,and to focus on the effect of impact loading on the stress field of the insulation coating on the outer ring during this special time period.The stress distribution of the coating under the influence of the impact load was obtained by varying the amplitude and frequency of the load.(4)The relationship between the thickness of the oxide layer and the state of crack propagation at the coating interface was obtained by scanning electron microscopy.In order to study the influence of coating thickness on bonding strength of coating and substrate,the adhesion of insulating coating with different thickness to substrate was measured by scratch meter.Temperature experiments were designed to study the decline of insulation performance of insulating coatings of different thickness under the condition of temperature rise.Combined with the results of scratch experiments,the value of coating thickness was studied to ensure both binding strength and insulation performance of the coating.