A METHOD OF DYNAMIC CHARACTERISTICS USING VIRTUAL MATERIAL EQUIVALENT BOLTED JOINTS

Abstract

The invention discloses a method for utilizing a virtual material to perform equivalence of dynamic characteristic of a bolting joint part. The bolting joint part is regarded as a plurality of virtual material layers, a finite element method is utilized to simulate stress conditions of different of bolting joint part at the contact areas under different bolt pretightening forces, and the contact pressure distribution of the bolting joint part is equivalent to be a fourth-order polynomial function with respect to the contact radius; an equivalent virtual material model of the bolting joint part is established by utilizing material mechanics knowledge, to determine a function relationship between the contact radius in an effective contact area and virtual material properties (elastic modulus, shear modulus, Poisson's ratio, density and virtual layer thickness); by the finite element method, two-layer, three-layer or more-layer virtual materials coupled with each substructure to establish a finite element model of the whole structure, and dynamic response analysis is performed, an obtained frequency response function is compared with modal test data to verify the correctness of the model, and the novel idea and method are provided for studying the dynamic characteristics of the bolting joint part.

Description

technical field [0001] The invention relates to the field of dynamic characteristics in the field of joint surface theory research, in particular to a method for equivalent bolted joint dynamic characteristics using a virtual material method. Background technique [0002] There are a large number of joints in the CNC machine tool, which destroys the continuity of the structure, thus showing complex dynamic characteristics, which greatly affects the dynamic performance of the whole machine. Studies have shown that the contact stiffness of the joint in the machine tool accounts for about 60% to 80% of the total stiffness of the machine tool, the contact damping of the joint accounts for more than 90% of the total damping of the machine tool, and the deformation caused by the joint accounts for about 40% of the total deformation of the machine tool. %~60%. Therefore, the research on the dynamic characteristics of joints is the key to the analysis of the mechanical system from ...

AI Technical Summary

Problems solved by technology

[0003] Spring-damper elements are usually used to simulate the dynamic characteristics of joints, but it is difficult to couple the stiffness and damping models with each substructure when using finite element simulation, and it is difficult to realize the dynamic characteristics of the overall structure through simulation technology

Using virtual materials to simulate the dynamic characteristics of bolted joints can greatly reduce the difficulties caused by finite element simulation, but the current research is to equivalent bolted joints to a layer of virtual materials, which is difficult to improve the simulation accuracy of the overall structure

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