Abstract
The present paper proposes a new numerical model for predicting the mechanical behavior of unidirectional composites, based on a 3D shear lag model. The present model considers the micro-damage including interfacial yielding. In order to confirm the validity of the present model, the simulated the ultimate tensile strength (UTS) is compared with the experimental result. Then, the damage process is researched by calculating the stress concentration factor (SCF) at the final failure plane.