Effects of the joint surface considering asperity interaction on the bolted joint performance in the bolt tightening process

Rough surfaces have a positive and important influence on the mechanical properties of the joint surface. Bolted joints are one of the common connection modes, whose assembly stiffness directly determines the machining accuracy of the machine tool. In this work, considering the joint stiffness between connectors, a mechanical model of the joint surface considering the asperity interaction is established based on fractal theory. On this basis, combined with the equivalent form of the bolted joint system, a new stiffness model depended on strain energy method is proposed. Then, the correctness of the proposed model is verified by experiments. Finally, through the application of FEA, the research on bolt tightening with different friction coefficients is completed. Results show that when the stiffness effect of the bolted joint surface is neglected, the equivalent stiffness of this system is too large, exceeding the accurate value by more than 20%.

Automated summary

This study investigates the influence of rough surfaces on the mechanical properties of joint surfaces. A mechanical model of the joint surface considering asperity interaction is established based on fractal theory. A new stiffness model based on strain energy method is proposed and validated through experiments. The research also includes the analysis of bolt tightening with different friction coefficients using finite element analysis. Results show that neglecting the stiffness effect of the bolted joint surface leads to an overestimated equivalent stiffness of the system.