A Method of Determining the Contact Area and Rigidity of Joint Surface Based on Surface Fitting

Abstract

A method for determining the contact area and stiffness of the joint surface based on surface fitting. First, the confocal microscope and three-coordinate measurement are used to measure the asperity, surface waviness and shape error of the mechanical joint surface, and the obtained point cloud data is used Fit the binary high-order function to obtain the final analytical formula of the contact surface, and then judge the position and direction of the contact point of the asperity, and perform the elastic Hertz contact calculation of a single contact point, and calculate the contact deformation under the action of force Finally, the overall contact area and contact stiffness of the contact surface are calculated, and the total contact area and contact stiffness in each direction are obtained. Compared with the traditional analytical method, this method has the advantage of being closer to the real shape; compared with the finite element method, This method expands the calculable contact area.

Description

technical field [0001] The invention belongs to the field of mechanical joint surface mechanics, and in particular relates to a method for determining the contact area and stiffness of a joint surface based on curved surface fitting. Background technique [0002] There are a large number of joint surfaces in complex mechanical systems such as machine tools, gas turbines, and automobile engines, which destroy the continuity of the mechanical system structure and affect the overall performance of the mechanical system to a large extent. The connection characteristics of the joint surface present a certain degree of nonlinearity, and introducing the characteristic parameter model of the joint surface into the modeling process of the whole system can effectively improve the performance prediction ability of the whole machine in the product design stage. Therefore, the accurate construction of the joint surface characteristic parameter model will provide a theoretical basis for t...

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Problems solved by technology

This research on microscopic contact behavior is based on many assumptions. Although the model has been developing and perfecting, the existing contact models basically still have the following problems: 1. The shape of the asperity is assumed to be Spherical or other simple shapes, which are far from reality; 2. When studying the contact behavior of the entire surface, it is assumed that the surface profile height distribution obeys a certain function distribution such as a normal distribution, and the statistical parameters of surface roughness such as the average radius of curvature are used. Starting from the real surface; 3. The research on the contact stiffness at the joint surface is limited to the rough scale level, without considering the influence of geometric shape, namely waviness, and macroscopic shape error on the contact stiffness of the joint surface

The existing finite element method can use real surface measurement data to study the contact problem, but because the finite element calculation needs to be divided into extremely fine grids, the size of the calculation area and the calculation efficiency are severely limited

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