Impact Shearing Fracture of Jointed Steel Plates of Overlap Bolted Joints

In the vehicle industries, collision safety and reliability of cars under impact loading become more and more important in recent years. This study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of an overlap bolted joint used in a car body, which contributes to crash simulations by computer-aided engineering (CAE). The impact behavior and fracture of jointed steel plates of the bolted joint are examined by experiments and numerical simulations. The specimens of jointed steel plates were made of a steel plate with tensile strength of 270MPa, while the jig plate is made of high tensile strength steel of 980MPa. The impact shearing test of the specimens was performed using the split Hopkinson bar technique for tension impact, together with the static test using a universal testing machine INSTRON 5586. Numerical simulations by FEM code LS-DYNA were also carried out to compare with experimental results and to understand the mechanism of fracture process of the overlap bolted joint plate. Good quantitative agreement was observed between the experimental results and the numerical simulations with respect to the behaviors of shear stress and deformation until rupture took place in the jointed steel plates. This study suggests that a stress-based fracture criterion may be developed for the impact fracture of jointed steel plates of an overlap bolted joint used in a car body.