Sensitivity Analysis of Factors Affecting the Clamping Force of High-Strength Bolts After Nut Corrosion

To analyze the sensitivity of factors affecting the clamping force of friction-type high-strength bolts (FHSBs) after nut corrosion, this study first simulates nut thickness and height corrosion using the nut cross-section loss method, considering the initial clamping force and nut diameter on the loss of clamping force of high-strength bolts. Then, a finite element (FE) model is established, and numerical analysis is conducted. Finally, the sensitivity of factors affecting the clamping force of high-strength bolts is studied. The research results show that the FE model established in this paper is in good agreement with the experimental results. The model’s calculation results are accurate and reliable, effectively simulating the clamping force loss of high-strength bolts after nut corrosion. The mechanical interlocking between the screw and nut threads transmits the clamping force, and the stress distribution in the middle part of the screw is relatively uniform, with the maximum stress located in the middle part of the screw. The farther away from the washer, the smaller the stress on the bolt head and nut, with the stress on the top edge of the nut being almost zero, presenting a U-shaped stress distribution. Sensitivity analysis indicates that nut corrosion height has the greatest impact on the loss of clamping force of high-strength bolts, followed by nut corrosion thickness, bolt diameter, and initial clamping force. These findings provide a valuable reference for the safety assessment of high-strength bolt connections after corrosion.