Microscopic Progressive Damage Simulation and Scale-Span Analysis of Cross-Ply Laminate Based on the Elastic–Plastic Theory

Computational mechanics has been carried out to study the microscopic failure mechanisms of cross-ply laminate. A microscopic model of fiber regular distribution near the [90/0]_8S laminate interlaminar zone is established, with two dominant damage mechanisms-matrix plastic deformation and interfacial debonding included in the simulation by the extended Drucker-Prager model and cohesive zone model respectively. The simulation results clearly reveal the damage process of the composites and the interactions of different damage mechanisms. It can be concluded that the damage of the [90/0]_8S RVE under tension initiates in 90° ply, and then intralaminar damage cracks spread to interlaminar cohesive region, which causes delamination between adjacent plies. Meanwhile in 0° ply, matrix plastic deformation and interface debonding occurs near the zone of interlaminar delamination expansion. While the damage of the [90/0]_8S RVE under compression initiates in 0° ply with fiber microbuckling and interfacial debonding, then the intralaminar degradations in 0° ply expand to interlaminar cohesive region, which produces a wide range of interlaminar delamination.