ANALYSIS OF THE MACROSCOPIC INTERFACIAL BEHAVIOUR OF THE FIBRE PULLOUT USING ELASTIC-PLASTIC COHESIVE MODEL

A single fibre pullout behavior from polymer matrix was analytically investigated in this paper. The elastic-plastic cohesive zone model was employed to simulate the crack propagation and interfacial failure. The critical fibre embedded length is determined, which distinguishes two pull-out processes from different fibre embedded lengths. There are different interface states during the fibre pull-out process. When the fibre embedded length is shorter than the critical length, the debonding force for the interface is linear relationship to the fibre embedded length; while the debonding force is approximately constant if the fibre embedded length excesses the critical length. The influence of the interfacial parameters on the debonding force is studied. Increasing the interfacial shear strength and the interface fracture toughness, or decreasing the displacement of crack initiation, can raise the debonding force for the interface. Without the interfacial frictional shear stresses after interfacial debonding, the peak load in the pullout force-displacement curve equals the debonding force for the interface. Under the influence of interfacial frictional shear stress, longer fibre embedded length and larger interfacial frictional shear stress lead to the peak load exceeding the debonding force.