Analysis of Pressure Distribution of the Bolted Joints Based on the Finite Element Method

Bolted joints widely exist in the fi eld of the national defense industry. However, its nonlinear stiff ness degradation will occur under tangential load which may lead to the reliability reduction. According to Coulomb friction theory, the pressure distribution is the key in the tangential degradation of bolted joints. Therefore, this paper aims to analyze the pressure distribution of bolted joints. Firstly, we established a threaded bolt model and two simplifi ed models. Secondly, the accuracy of the three models describing the contact area is verifi ed, and the infl uence of preload and material properties on the contact radius is analyzed. Thirdly, we compared the pressure distribution of the three models, and results show that the smooth bolt model is more suitable for pressure analysis. Finally, the accuracy of several diff erent functions to characterize the pressure distribution of bolted joints is analyzed, and results indicated that the Fernlund function is optimal. This paper provides a feasible simplifi ed bolt model for fi nite element analysis, and the optimal pressure distribution function can be applied in the tangential stiff ness degradation modeling.