Original Paper(Vol.60 No.7 pp.662-667)

Impact Pull-Out Fracture of Steel Plates Jointed by Bolt

Yoshiaki UEMURA, Yasuhiro AIHARA, Masashi DAIMARUYA, Hiroyuki FUJIKI, Hidetoshi KOBAYASHI and Katsumi NAGAI

Abstract:Collision safety and reliability of cars under impact loading become more and more important in the vehicle industries. This study is concerned with the development of a fracture criterion for the impact fracture of jointed steel plates of a bolted joint used in a car body, which may contribute to crash simulations by computer-aided engineering (CAE). The impact behavior and fracture of jointed steel plates of a bolted joint were examined by experiments and numerical simulations. The impact pull-out test of jointed steel plates by a bolt was performed by making use of an one-bar method for impact tests, together with the static test using a universal testing machine INSTRON 5586. In order to understand the mechanism of fracture process of the jointed steel plate, numerical simulations by FEM code ANSYS and LS-DYNA were also carried out. The rupture of steel plates jointed by a bolt with washers occurred along the circular outside of washers and made a hole with the same diameter as washers for both of static and impact loading conditions, and then the pull-out load (F) increased with increasing of the diameter of washers. On introducing the pull-out stress defined as (F/A) for convenience, in which A is the cross-sectional area of the steel plate along the circumference of a washer, the pull-out strength showed almost the same value regardless of the washer size. This result suggests that a stress-based fracture criterion may be developed for the impact fracture of jointed steel plates of bolted joint used in a car body.

Key Words:Impact pull-out strength, Jointed steel plate, Bolted joint, One bar method, Car, CAE