Analysis of stress transfer in rectangular patch-reinforced composites with unidirectional or bidirectional interfacial damage under tensile loading

This paper proposes a modified two-dimensional (2-D) shear-lag model considering unidirectional or bidirectional interfacial damage to analyze the stress transfer mechanism of rectangular patch-reinforced composites under tensile load. The semi-analytical solutions for bidirectional normal stresses and interfacial shear stresses are provided, accounting for interfacial orthotropic anisotropy and the stiffness variation in the damage stage. The study examines the influence of material parameters, including the difference in Poisson's ratios between the substrate and patch, thickness ratio, and aspect ratio, on interfacial damage in composite materials. The results show a good agreement between the stress distribution solutions predicted by the proposed 2-D model and finite element results. The model provides an effective solution to the 2-D stress problem in rectangular patch-reinforced composites with interface damage.