Abstract
Damage ahead of notch tips in random fiber reinforced SMC composites consists of a group of microcracks. In this paper, the computational simulation method of the damage extension is proposed by making a model of the damage mechanism and applying the concept of fracture mechanics to the formation of damage. From observations of the damage, we realized that the damage zone consists of matrix cracks and debondings of strands and only bridgings of strands bear the load in the damage zone. We first derive the governing equation of the formation of damage, which is the relationship between the released elastic strain energy and the compliance. Then, in view of this equation and the stochastic process of strand breakage, the damage extension behavior is computationally simulated with the finite-element method, in which the damage zone is made of the truss to consist of debonding strands bridging inside. The computational simulation results appear to be in agreement with the experimental results, and we come to the conclusion that the proposed simulation method is useful for the evaluation of fracture behavior of random fiber reinforced SMC composites.
