Variation in the nonlinear stiffness of bolted joints due to tangential hysteresis behavior

Obtaining the stiffness variation characteristics of a bolted joint during service is essential for predicting the response of an entire structure. In this study, we propose a relationship between the macro deviation, micro-topography of the bearing surface, and hysteretic characteristics of a bolted joint. We first analyze the stiffness variation caused by the hysteretic characteristics during the tightening and service processes. Next, we investigate the influence of non-parallel bearing surfaces and displacement loads on pressure distribution and stiff-ness, both at macro and micro scales, using Finite Element Modeling (FEM) and experiments. Finally, we compare data from a hysteresis behavior test of a single-bolt lap beam with the FEM simulation results. The comparison demonstrates that macro deviations in the bearing surface alter the preload after assembly, while the bearing surface experiences dynamic changes in pressure due to microtopography and cyclic displacement loads. Consequently, this leads to irregular dynamic changes in joint stiffness during the service process, significantly affecting the dynamic/static response of the bolted assembly structure.

Automated summary

This study investigates the factors influencing the stiffness variation characteristics of a bolted joint during service, including macro deviation, micro-topography, and hysteresis characteristics. Through experiments and finite element modeling analysis, it is found that macro deviations and micro-topography on the bearing surface can cause irregular dynamic changes in the stiffness of the bolted joint, significantly affecting the dynamic/static response of the entire structure.