MODELLING AND SIMULATION OF THE DEBONDING BEHAVIOUR OF WIRE REINFORCED ALUMINIUM MATRIX COMPOSITES

Abstract

An axisymmetric cylindrical finite element model is presented with the objective of evaluating the interfacial properties of wire-reinforced aluminium matrix composites. It consists of a wire of stainless spring steel 1.4310 (X1OCrNi18-8), a matrix of aluminium alloy AA6060 and the interface. The finite element model is used to model the push-out-test which has been developed over a number of years as a mean of quantifying the interfacial properties. The interface with a specified thickness is modelled using the cohesive layer concept where, in addition to the elastic parameters, a damage criterion based on the maximum nominal stress is also defined for the interface. Fracture energy is used to define the damage evolution which describes the rate at which material degrades, once the damage initiation criterion is met. The interface parameters are varied to adopt the model according to the experimental results reported in the past. The simulation results are in qualitative agreement with experimental results regarding the force-displacement-graph. The simulation results obtained show the presence of compressive stresses at the top and tensile stresses at the bottom of the interface caused by the bending of the specimen. It indicates that, during fibre push-out-test of metal matrix composites where thin-slice geometries are used, interfacial failure initiation favoured by tensile stress field, probably occurs at the bottom of the specimen even in the absence of thermally induced shear stresses. However, modelling the stepwise debonding of interface requires the more sophisticated implementation of interface behaviour concerning failure evolution and the friction between wire and the matrix