Modeling of Fiber Kinking Damage for Bearing Failure in Bolted Joints of CFRP Laminates

This paper experimentally investigates damage mechanisms which is closely related with the bearing failure in bolted joints of CFRP laminates and proposes a finite element model to reproduce those damage mechanisms. First, the damage was observed in the bearing failure of bolted joints, and the main factor of the large stiffness degradation in bearing failure is the fiber kinking damage. In addition, the fiber kinking is suppressed by the bolt clamping, which increases the bearing strength of bolted joints. Then, three-dimensional finite element model was developed for addressing the bearing failure in bolted joints based on the experimental observation. In this model, the initiation and the propagation of the fiber kinking damage which plays an important role in the bearing failure of bolted joints were reproduced and the stress failure criteria were investigated. The variation of the load at the kinking onset due to the bolt clamping was simulated and consequently the load history during the evolution of the fiber kinking damage was simulated.