拉伸板中心孔干涉配合对载荷幅值的影响

为研究干涉配合中被连接件最小截面（SCS）所传递载荷（截面载荷）的幅值得以降低的原理，按一定规律对销钉与板进行分区，并将其用同等刚度的弹簧代替，建立了销钉干涉配合的弹簧分析模型，进而从弹性角度解释了干涉配合中板的最小截面所传递载荷的幅值得以降低的原因。基于该模型分析了静载下截面载荷随外载的变化规律，得到了循环载荷下截面载荷幅值与外载幅值间的关系，其与有限元分析（FEA）结果之间的最大误差不到20%。分析发现：连接件与被连接件间的接触力随外载变化的自动调节作用是截面载荷幅值降低的原因；对于特定的绝对干涉量，干涉配合只对一定范围内的外载具有调节作用。当外载在干涉配合的有效影响区时，截面载荷幅值的降低程度完全决定于连接件与被连接件的相对刚度；若外载过大使得钉孔发生分离，干涉配合不仅对载荷幅值不再具有调节作用，还容易引起钉孔接触面的微动磨损。

Effect of Interference-fit on Load Amplitude of a Single Central Holed Tensile Plate

To study the mechanism of the load amplitude reduction in smallest cross section (SCS) of an interference-fit connection, a spring analytical model of interference-fit pinned joint is developed by means of partitioning the pin and the plate and substituting each section with a spring of equal stiffness. The reason why the load amplitude in interference-fit connection is reduced is elaborated by using the spring model. The dependency of the resultant in the SCS the joint on external static load is investigated, and the relationship between the load amplitude in SCS and that of external cyclic load is also obtained, the discrepancy between which and the results of a finite element analysis (FEA) model is less than 20%. Analytical result reveals that the key to the loss in load amplitude lies in the contact pressure between the pin and the plate, and interference with a certain magnitude works only when the magnitude of external load is under a certain value. When external loading is in the effective range of the interference-fit, the load amplitude in cross section would be reduced to what extent is totally determined by the relative stiffness of the components of the joint. Over loading that initiates the separation of the pin and the plate, invalidates the effect of interference in terms of reducing load amplitude, and further gives rise to fretting fatigue of the contacting interface.