Investigation on Bearing Capacity and Fracture Behaviour of the Bolt in a Flange Connection Considering Multiple Load Cases

In this study, the bearing capacity and fracture behaviour of the superalloy bolts that are commonly used to connect thin-walled structures in aerospace engineering, are investigated. Various load cases (tension, bending, shear, and torque loadings, as well as any combination thereof) are considered in the bolted connection. First, a bolted connection under combined tension–bending loading is considered. The ultimate load calculated by the finite element analysis is compared with that of the experimental test. A single-bolt equivalent model is proposed to reduce the computational cost of the fracture analysis. The parameters in the Johnson–Cook(J–C) model can be efficiently calibrated using the equivalent model. The bolted connection under combined tension–bending–shear loading is further studied using the modified J–C model. Subsequently, a fastener bolted preload is generated by imposing torque loading on the bolt. The bolt torque–preload relationships obtained by the finite element simulation and different theoretical methods are compared. A failure analysis of bolted connections under combined torque–tension loading is conducted. Finally, an ABAQUS plug-in is developed to achieve parametric modelling and a numerical simulation of bolted connections with preloads and multiple loads.