Modeling And Research Of Normal Contact Parameters Of Mechanical Joint Surface

The mechanical components consists of quite a few parts.So they are not a single individual.The mutual contact between the parts,the joint surface is formed on the surface of the parts.The different surface roughness of the parts,the contact gap between parts has great influence on the entire performance and usage.A large number of asperities are distributed on the contact surface.The asperities characteristic parameters are a crucial factor about affecting the dynamic characteristic parameters of the joint surfaces.Joint surface contact stiffness is an important source of reliability for the mechanical parts.The parameters such as joint surface contact damping and the coefficient of firction,affect the sealing and heat dissipation properties of the mating parts.Based on contact mechanics and Hertz contact theory,this paper emphasizes the following aspects:Firstly,analysis the two-dimensional fractal surfaces contact parameters.The fractal dimension has an important influence on the relationship between the normal contact load and the stiffness.When the fractal dimension is less than1.5,the function between the contact load and the stiffness shows an exponential growth trend.When the fractal dimension is greater than 1.5,the relationship between the contact load and the stiffness shows a linear growth relationship.For the three-dimensional fractal surface,the dividing line is 2.5.The fractal dimension is less than 2.5,the function shows an exponential growth trend.The fractal dimension is greater than 2.5,the relationship shows a linear growth relationship.Secondly,the finite element modeling method has high accuracy.It was used to anatomize the modeling of a single asperity and the entire joint surface.And the collected data is processed via the training method of machine learning.It is found that the finite element analysis data has 98% similar with the theoretical results.Collecting data about the system load and the relative acceleration by setting up a test bench.The acquired acceleration signal isconverted into a displacement signal by a control system.Through data training and machine learning.By comparison with the theoretical data,the error is also within reasonable limits.Finally,the machining process will inevitably have vibrations,and the quality of the parts will be greatly affected.Based on this situation,taking into account the influence of the minor deformation of the asperity on the normal contact stiffness of the mechanical joint surface.With the load increasing,the asperities have three deformation stages.The dimensionless fractal model and the normal contact stiffness and the normal contact stiffness is established.When the normal contact load is kept constant,the normal contact stiffness is increasing with the increase of the deformation amount,and the larger the fractal dimension,the more the stiffness increases.