| The fretting fatigue is widely found in the industrial production.The fatigue caused by the fretting phenomenon shortens the crack initiation and expansion time of the component,reduces the service life of the fretting component,and further leads to the unpredictable loss of property.With the progress of human understanding and the continuous improvement of technical level,surface engineering technology is widely used in various industrial fields.In order to reduce the material wear and the formation of cracks,coating is disposed on the surface of specimen for extending the service life.In this paper,a finite element analysis model of fretting fatigue with coating is established.The contact stress on the coating surface of the fretting specimen is discussed by numerical simulation.This thesis discussed the influence to the fatigue life with different coating thickness,elastic modulus ratio of coating to specimen and friction coefficient.The research contents and achievements of this paper are as follows:(1)The finite element model of the cylindrical fretting pad and specimen was established in ABAQUS.Based on the Hertz contact theory,the model which is kept within the ideal error range,and the accuracy of the finite element result is verified.Then a fretting fatigue model with coating was established based on this model.(2)This thesis has studied the effects of coating thickness,elastic modulus ratio of coating to specimen,and friction coefficient on the stress field of the contact area.As the increases of the coating thickness,the stress along the tangential of contact surface increases,the Mises stress increases and sudden changes along the y-axis on the interface of coating,the stress gradient(the amount of mutation)increases,the shear stress increases first and then decreases,and the contact half width decreases.The larger of elastic modulus ratio of coating to specimen,the larger of the normal contact stress to the coating surface.The Mises stress has a sudden change along y direction,and it also increases.With the increase of elastic modulus ratio,the maximum shear stress increases,on the contrary,contact half width of fretting area decreases.With the increase of the friction coefficient,the shear stress peak at the interface of fretting fatigue contact surface and coating plane specimen increases,the contact half width is basically constant.(3)Based on the critical surface method,the SWT fretting fatigue life prediction model was used to analyze the influence of different coating thickness,elastic modulus ratio of coating to specimen and friction coefficient.With the increase of coating thickness,the fretting fatigue life of coating cylindrical pad and flat specimen also increases.With the increase of elastic modulus ratio,the fretting fatigue of coating model decreases.The life of the coating model decreases with the increase of the friction coefficient. |
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