Finite element modeling and simulation of the fiber–matrix interface in fiber reinforced metal matrix composites

Abstract

The properties of fiber–matrix interface in the fiber reinforced metal matrix composites (MMCs) have been investigated in the past with the use of push-out test. The finite element (FE) analysis which is used to model the push-out test helps the composite’s designer in optimizing the interfacial properties. A two dimensional planar FE model is presented for investigating the properties of interface. Cohesive layer concept is used to model the interface with a specified thickness. The initial response of the cohesive element is assumed to be linear elastic. The maximum nominal stress criterion is used to define the damage initiation and the damage evolution is defined in terms of fracture energy. The simulation results show that the cohesive layer behaves almost like the matrix for the linear elastic deformation prior to damage. It is concluded that the values of Young’s modulus and shear modulus for the cohesive layer can be taken equal to that of the matrix material for the finite element simulation of the debonding behavior of these MMCs. Furthermore, it is observed that the shear stress at which damage initiates can be determined by using the cohesive layer concept for the interface. Once a damage initiation criterion is met, material damage occurs in accordance with the defined damage evolution law. The complete failure of the interface takes place when the stress becomes zero. However, the interface behavior needs to be defined in a more sophisticated way so as to model the stepwise debonding and failure evolution once the complete debonding has occurred.