This article presents a detailed analysis on stress concentration in notched unidirectional fiber-reinforced composites. Due to the formation of longitudinal splitting at notch tips along the fiber direction, the extremely high stress concentrations ahead of the notch tips could be drastically reduced for composites under remote tension. The inability of the widely used material property degradation method to accurately redistribute the local stresses at the notch tips is examined. The notch blunting effect is investigated by modeling the longitudinal splitting as a thin plastic cohesive layer or debonding, and results for the stress redistribution in the unnotched section directly ahead of the notch tips are presented. By introducing the intra- and inter-ply damage modes, the failure of a double-notched cross-ply laminate is predicted and compared with the experimental results from open literature.
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