Study On Contact Mechanical Properties Of Asperity With Inclusions

In mechanical equipment,contact components are widely used,such as bearings,gears,rails,etc.,whose contact mechanical properties are significantly affected by material cleanliness.In industrial production,due to many factors,such as cleanliness of materials,requirements of process and restrictions of industrial environment,non-metallic inclusions will remain in materials.The seemingly smooth surface of the material is composed of asperity of different sizes when viewed under a microscope.The inclusions near the contact surface actually exist in the asperity of different sizes.In the element contact into,the inclusion of asperity contact with obvious impact on performance,it may induce plastic deformation of asperity,under the rolling circle contact,can cause the accumulation of plastic deformation,resulting in crack initiation and propagation,the serious influence material of rolling contact fatigue life(RCF)life,Therefore,it is very necessary to study the elasticity and elastic criticality of the asperity with inclusion.In this paper,inclusions are divided into nonmetallic inclusions and cavities according to their different properties,and nonmetallic inclusions are divided into soft inclusions and hard inclusions.Based on the contact model between rough surfaces,a contact mechanical model of a single asperity with a single inclusion was established.The corresponding finite element model was established by using the finite element software ABAQUS,and the correctness and accuracy of the model were verified by various methods.The influence of inclusions on the elastic deformation and elastic critical deformation of the asperity was studied by the model.The influence of inclusions on the initial plastic yield of the asperity was found,and the essential differences of the different effects of soft inclusions,hard inclusions and cavities on the asperity were analyzed from the perspective of stress.Soft inclusion,hard inclusions and cavity are researched of asperity elastic critical interference(Interference corresponding to the first plastic yield of asperity),the influence of the inclusion size,depth of the inclusion,elastic modulus of inclusion and asperity size,elastic modulus of asperity,yield strength of asperity is considered,the results are presented as analytical solutions.The influence of inclusion on the surface contact pressure of asperity is studied.The results show that the inclusions have obvious influence on the surface contact pressure distribution of the asperity.Soft inclusions and cavities lead to the "sag" of the contact pressure at the inclusion site,while hard inclusions lead to the bulge".It is found that the different parameters of inclusions and asperity have a great influence on the amplitude of "sag" and "bump".The influence of inclusion size,inclusion depth,elastic modulus of inclusion,size of asperity and elastic modulus of asperity on the contact load is obtained by calculation.The results are given in the form of analytical solution.At the same time,it is proved that the cavity is a limiting case of soft inclusion by comparing the influence of the cavity and the soft inclusion on the contact performance of the asperity.