Imperfect interlaminar interfaces in laminated composites: delamination with the R-curve effect

Damage models based on imperfect interface and steady-state R-curve concepts are proposed to describe the development of delamination mechanisms in laminated composites. Different energy absorbing sources are taken into account: (i) an intrinsic fracture toughness resulting from actual adhesion bonding at interfaces, and (ii) additional energy dissipated during delamination development process. Hence, the resistance to delamination of composite laminates is represented completely. Simulation results are in good agreement with available experimental data on DCB and ELS test specimens, respectively, dedicated to mode-I and mode-II fracture toughness assessment. R-curve effects, either caused by fibre bridging or void formation are properly simulated.