Study On Inelastic Contact Mechanics Of Finite Body With Inclusions

Mechanical components are an extremely important part of modern industry,playing a vital role in many areas of manufacturing,the accurate prediction of its service life is extremely important,many scholars have found that the rolling contact fatigue life of mechanical components is shortened mainly by the impact of inclusions below the contact surface.The existence of non-metallic inclusions will lead to stress concentration below the contact surface of mechanical components,which will lead to the sprouting of cracks,and when the cracks extend to the surface of mechanical components,pitting or fatigue fracture will occur,so there is an urgent need to study the influence of non-metallic inclusions on the contact performance of mechanical components.In this thesis,a finite body contact mechanics model containing a single inclusions is established according to the real mechanical component surface contact,and the corresponding finite element model is established by ABAQUS software,through which the effect of nonmetallic inclusions on the finite body contact mechanics properties in the elastic-plastic stage is studied.First,the effects of different hard inclusions on the contact mechanical properties of the finite body in the elastic-plastic stage were studied.The variation of the plastic region below the contact surface of the finite body in the presence of hard inclusions and the effect on the Mises stress region of the finite body were analyzed,and their effect on the critical downward pressure amount for the initial plastic yielding of the finite body was investigated and the results were fitted to the equations.The contact load and contact area curves of the finite body with inclusions are obtained and the results are presented in the form of analytical solutions.Secondly,the effect of soft inclusions on the contact mechanical properties of the finite body in the elastic-plastic phase is investigated.The effect of soft inclusions on the plastic region below the contact surface of the finite body is analyzed.The Mises stress inside the soft inclusions will be smaller than that of the finite body,and the effect of different soft inclusions on the critical downward pressure of the finite body is fitted to the equation.The soft inclusions will reduce the contact pressure on the surface of the finite body and cause the phenomenon of"depression",and with the increase of the downward pressure,the soft inclusions will also increase the contact pressure on the surface and cause the situation of "bulge".The effect of soft inclusions on the contact load and contact area of the finite body is analyzed,and the results are fitted to the equation and extended to the finite body with inclusions.Finally,different shapes of inclusions with the same depth and volume are investigated,and it is found that different shapes of inclusions have different effects on the Mises stress on the finite body,and the inclusions with sharp corners have stress concentrations at their sharp corners.When the shape of inclusions changes,the effect of inclusions on the contact mechanical properties of finite bodies also changes,but their effect on the contact mechanical properties of finite bodies has a consistent trend.