Mechanical Analysis of a Pin Interference-Fitted Sheet under Tensile Loading

摘要

Interference fit can lead to better fatigue behavior of mechanical fastened joints. To explore the fatigue enhancement mechanism of interference fit, an analytical model of an interference-fit pinned sheet under subsequent tensile loading is presented. This model is employed to correlate the bypass load with the external longitudinal tensile load of the sheet, and the range of the two forces. Three-dimensional (3D) finite element (FE) analysis is performed using ABAQUS and comparison between the results of the two models shows a good agreement. Analytical results reveal that the key to the reduction of the bypass load amplitude lies in the elastic deformation of connected members of interference-fitted joints and the contact between them. This effect is accomplished through the automatic adjustment of the contact at the interfaces of the pin and sheet. For a specific joint, the effective affecting range (EAR) of interference for external loading is dependent on the interference and stiffness of its members. Specifically, the bypass load amplitude can be reduced only when external loads intersect EAR with a nonempty subset. If exerted loads are entirely within EAR, the bypass load amplitude can be minimized and the reduction ratio depends solely upon the stiffness of the connected members. It is also concluded that taking into consideration the external loads, especially its maximum value, is essential in the optimizing of interference. Finally, the optimum interference is deduced via the analytical model.