Microscopic progressive damage simulation of unidirectional composite based on the elastic-plastic theory

Computational mechanics has been carried out to study the microscopic failure mechanisms of unidirectional fiber-reinforced polymer composites. A representative volume element of fiber random distribution based on molecules random collision model 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 transverse tension fracture initiates as interfacial debonding and evolves as a result of interactions between interfacial debonding and matrix plastic deformation, while the compression failure is dominated by matrix plastic damage. The longitudinal tension and compression are both dominated by fiber breakage, but longitudinal tension initiates as matrix plastic damage and longitudinal compression initiates as fiber microbuckling. Finite element method appropriately simulated the process of progressive damage of the fiber buckling failure, which is consistent with the observed result under scanning electron microscopy.