Interval estimation for contact stiffness of bolted joint with uncertain parameters

Yongsheng Zhao,Hongchao Wu,Qiang Cheng,Congbin Yang,Zhifeng Liu

doi:10.1177/1687814019883708

Yongsheng Zhao, Hongchao Wu + Show 3 more

Open Access

https://doi.org/10.1177/1687814019883708

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Abstract

Bolted joints are elements used to create resistant assemblies in the mechanical system, whose overall performance is greatly affected by joints’ contact stiffness. Most of the researches on contact stiffness are based on certainty theory whereas in real applications the uncertainty characterizes the parameters such as fractal dimension D and fractal roughness parameter G. This article presents an interval estimation theory to obtain the stiffness of bolted joints affected by uncertain parameters. Topography of the contact surface is fractal featured and determined by fractal parameters. Joint stiffness model is built based on the fractal geometry theory and contact mechanics. Topography of the contact surface of bolted joints is measured to obtain the interval of uncertain fractal parameters. Equations with interval parameters are solved to acquire the interval of contact stiffness using the Chebyshev interval method. The relationship between the interval of contact stiffness and the uncertain parameters, that is, fractal dimension D, fractal roughness parameter G, and normal pressure, can be obtained. The presented model can be used to estimate the interval of stiffness for bolted joints in the mechanical systems. The results can provide theoretical reference for the reliability design of bolted joints.

Highlights

Accounting for up to 50% of the total stiffness of the mechanical system, the stiffness of bolted joint can affect the overall performance of systems.[1]
The stiffness of the bolted joint can be obtained by testing of static loading deformation,[10] and Daisuke et al.[11] introduced this method to approximately solve the contact stiffness by the fitting method. They applied the stiffness parameter to finite element model (FEM) analysis of a machine tool, in which the results show that the FEM with the contact stiffness is considered to be closed for the machine–foundation interface
Interval models of uncertain parameters are introduced to the fractal model and the equations are solved through the Chebyshev interval method

Summary

Introduction

Accounting for up to 50% of the total stiffness of the mechanical system, the stiffness of bolted joint can affect the overall performance of systems.[1]. Keywords Bolted joint, fractal theory, Chebyshev interval method, stiffness estimation, uncertain parameters In the traditional stiffness model based on fractal contact theory, the researchers assumed that the fractal dimension, fractal roughness parameters, and bolt pre-tightening force are considered as the certainty parameters.

Results

Conclusion