Fiber push-out study of a copper matrix composite with an engineered interface: Experiments and cohesive element simulation

The fiber push-out test is a basic method to probe the mechanical properties of the fiber/matrix interface of fiber-reinforced metal matrix composites. In order to estimate the interfacial properties, parameters should be calibrated using the measured load–displacement data and theoretical models. In the case of a soft matrix composite, the possible plastic yield of the matrix has to be considered for the calibration. Since the conventional shear lag models are based on elastic behavior, a detailed assessment of the plastic effect is needed for accurate calibration. In this paper, experimental and simulation studies are presented regarding the effect of matrix plasticity on the push-out behavior of a copper matrix composite with strong interface bonding. Microscopic images exhibited significant local plastic deformation near the fibers leading to salient nonlinear response in the global load–displacement curve. For comparison, uncoated interface with no chemical bonding was also examined where the nonlinearity was not observed. A progressive FEM simulation was conducted for a complete push-out process using the cohesive zone model and inverse fitting. Excellent coincidence was achieved with the measured push-out curve. The predicted results confirmed the experimental observations.