A novel bolted joint model with stick-slip hysteresis properties considering pressure-dependent stiffness: Theoretical and experimental investigations

Considering the influence of normal pressure on tangential stiffness, in this paper, an improved Iwan model with pressure-dependent stiffness is proposed to better describe tangential stick-slip hysteresis behaviors of bolted fiber-reinforced composite joints. In the model, the expression of the force-displacement relationship is derived from the evolution of the slip area. The parameters of the model are obtained based on multi-scale fractal contact theory, which avoids the inconvenience of parameter estimation methods requiring special quasi-static experi-ments. Meanwhile, the tangential behavior experiment of bolted fiber-reinforced composite joints is carried out. By comparing the hysteresis curve results and the stiffness softening law, the accuracy of the model and the necessity of considering the pressure dependence of the tangential stiffness are proved.