Effect of misaligned plates and varying interfacial area on bolted structures

Abstract

The perfect alignment of holes cannot be guaranteed while assembling the parts using the bolted joint. The misalignment of plates affects the contact pressure distribution at the bolted plate interface. In addition, the varying contact area at the bolted joint interface affects both the friction and the contact pressure distribution. The variation in the contact pressure and friction at the interface affects the dynamic behavior of the bolted structure. Accuracy of frictional energy dissipation is a prerequisite in predicting the dynamics of the bolted structure. Driven by this demand, we have developed an analytical model to predict the effect of hole misalignment and varying plate interface area on the frictional energy dissipated by the bolted structure. For misaligned bolted plates, we observed an asymmetric hysteresis loop with different maximum and minimum force magnitude. In addition, the bending of the bolt shank for misaligned holes is also observed. The contact area between plates does not affect the energy dissipation when contact pressure drops to zero at the plate interface. However, when the contact pressure does not drop to zero, the contact area between plates affects the energy dissipation and the tangential stiffness of the bolted joint. All these phenomena are modeled using the Iwan-based analytical models developed using the pressure profile obtained from the FEM simulation result. The developed analytical model is validated using the hysteresis loop obtained from FEM simulation results. It is observed that the developed analytical model can predict all the phenomena discussed above and can capture the hysteresis loop with reasonable accuracy for all the cases considered.