A Three-Dimensional Transition Interface Model for Bolt Joint

Workpiece-fixture contact stiffness is an evaluation criterion for machining stability, and its effective prediction involves contact state analysis, surface profile analysis, and modeling of fixture and workpiece geometries, presenting a multi-source complexity. In this paper, a fractal theoretical model of contact stiffness under curved surface contact state is proposed, and the domain expansion factor and substrate deformation are considered to improve the prediction accuracy. First, based on the geometric theory and trigonometric function, the fractal theory model of microconvex body-curved surface contact is established. Then, the curved surface contact is equated to rough curved surface and smooth rigid curved surface, and analyzes the mechanical mechanism of the microconvex body-curved surface contact. Considering the influence of domain expansion factor and substrate deformation on total deformation, a fractal model of curved surface contact stiffness is obtained by force balance constraints. Then, a contact stiffness solution based on the adaptive Simpson's algorithm is proposed. Finally, the support-adsorption composite fixture is developed, and the model is verified through experiments. The results revealed that the average prediction error of the theoretical model is 11.24%. As the fractal dimension increases, the scale factor decreases, the contact stiffness gradually increases, and the fractal dimension is recommended to be limited to 1.7. Clamping force increases, intrinsic frequency and contact stiffness increase. In the case of a small initial support force, the phenomenon of increasing contact stiffness caused by the adsorption effect is more obvious, and the adsorption radius is not recommended to take a smaller value, such as 5-10mm. Support-absorption composite fixture increases contact stiffness while reducing clamping deformation.

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Equivalent Dynamic Modeling for the Relative Rotation of Bolted Joint Interface Using Valanis Model of Hysteresis

Zhang

Liu

2023

Machines

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Dynamic modeling of the joint interface is critical to the performance analysis of bolt-jointed structures. In this work, an equivalent modeling method was presented for modeling the relative rotation of the joint interface in bolt-jointed beam structures. As the transverse vibration of the studied structure is closely related to the rotation of the joint, which is different from previous studies that focused on the tangential slip of the joint interface, the Valanis model is used to model the relative rotation of the joint. In addition, the shear deformation and rotational inertia of the beam were considered in the modeling, using a finite element method that employed Timoshenko beam elements. The parameters of the Valanis model were determined by fitting a series of hysteresis loops obtained from the transient nonlinear analysis of a 3D FEM model. The results show that the proposed equivalent modeling method can accurately simulate the dynamic response and dissipation of the jointed beam structure with a significantly high computational efficiency. The maximum errors of the dynamic response amplitude and the energy dissipation are 5.5% and 8.3%.

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A Three-Dimensional Transition Interface Model for Bolt Joint

Cited by 3 publications

References 34 publications

Theoretical and experimental studies on vibration characteristics of bolted joint multi-plate structures

Theoretical and experimental studies on vibration characteristics of bolted joint multi-plate structures

Prediction of curved workpiece-fixture contact stiffness based on fractal theory

Equivalent Dynamic Modeling for the Relative Rotation of Bolted Joint Interface Using Valanis Model of Hysteresis

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