Wire–matrix debonding under transverse load: Inverse identification of a cohesive zone model for the interface

A methodology for identifying the cohesive properties of a wire-matrix interface is proposed. A single steel wire is embedded in an epoxy matrix and the system is subjected to uniaxial tension. The interface debonding is optically monitored, based on a so-called through-light measurement of the crack extent. Crack initiation occurs abruptly at the wire poles and is followed by a controlled crack growth, along the interface. These in-situ observations are used to identify the interface parameters related to a cohesive zone model using a 2D plane strain finite element analysis. A two-stage identification process is described. A restricted set of parameters is first determined using the crack nucleation step, then an optimum set of parameters is determined by focusing on the subsequent controlled crack propagation.