Abstract: Bolted joints are widely used in mechanical structures. There are multiple nonlinear behaviors on the connection interface, which affect the stiffness and damping of the connection structure, and further cause the nonlinear changes in dynamic characteristics. Therefore, the establishment of a simplified model that can reproduce the complex nonlinear characteristics between the connection interfaces and further identify the model parameters accurately is of great significance for the research on the dynamic and static characteristics of structures with bolted joints. A nonlinear model of connection interface of bolted joints is established, and an identification method for model parameters based on quasi-static experiments is proposed. First, the normal nonlinear contact stiffness and various contact states such as stick, slip, and separation on the interface are considered in the modeling. Furthermore, the hysteresis curves and tensile-compressive deformation curves of the connection interface are obtained through quasi-static experiments, and the proposed identification method is applied to an example. The results show that the theoretical and experimental results are in good agreement, and the identification method has high accuracy.

Key words: interface of bolted joints, nonlinear modeling, parameters identification, quasi-static experiment