A Modeling Method to Describe the Response and Failure of Bolted Joints Subjected to Impact Loading

Bolted lap joints have been widely used in various engineering structures such as construction, aerospace, and transportation due to their advantages of simplicity, cost-effectiveness, and assembly. The ductile response provided by bolted joints is vital when subjected to impact loading caused by explosions and collisions. The plastic deformation can effectively absorb the impact energy, thus delaying the overall fracture of the structure. This work investigates the complete process of sticking, slipping, collision and fracture of a bolted structure under impact loading. Specifically, a high-fidelity finite element model of the bolted lap joint was developed to simulate the fracture process of the bolted lap joints under different impact velocities, with the displacement-load curves obtained. The fracture characteristics of bolted lap joints subjected to shear loads in the simulation results are in agreement with a large number of experimental results. While the ductility of the structure decreased as the impact load increased. Subsequently, this paper proposed a combined dynamic Iwan model that considers the entire process of friction, slip, collision, and fracture. The friction and slip processes were based on the classical Iwan model, while the plastic collision process of the bolt was based on the J-C plasticity model. Thus, a model was constructed that accounted for the power function relationship of strain and the strain rate effect. The results of the proposed dynamic Iwan model fitted well with the high-fidelity finite element model. In addition, the dynamic Iwan model has very low computational consumption.