Micro–Macro Coupling Study on Pseudo‐Ductile Tensile Behavior of Thin‐Ply Carbon Fiber Laminates With Angle‐Ply and Discontinuous Fiber Structures

Thin‐ply angle‐ply fiber‐reinforced polymer composite (FRP) laminates can exhibit pseudo‐ductility that provides warning before catastrophic fracture. Therefore, understanding the micro‐mechanisms behind the pseudo‐ductility is particularly crucial. This study investigated the pseudo‐ductile tensile behavior and damage mechanisms of thin‐ply angle‐ply carbon fiber‐reinforced polymer composite (CFRP) laminates with continuous and discontinuous fiber structures. Continuous CFRP laminates with layups of [(± θ ) 5 ] s , where θ = 0°, 15°, 25°, and 45°, were fabricated and tested under quasi‐static tension. Complementary representative volume element (RVE) models were developed to extend the angle gradient. Discontinuous CFRP laminates with [(± θ ) 5 ] s were further prepared and analyzed using a macroscopic finite element model to clarify the influence of fiber discontinuity on damage evolution. Results showed that increasing the fiber angle reduced the tensile properties but substantially enhanced pseudo‐ductility. Compared with [(0) 20 ], the elastic modulus and tensile strength of [(±25) 5 ] s decreased by 65.1% and 47.9%, respectively, whereas the pseudo‐ductile strain increased from 0.12% for [(±15) 5 ] s to 12.73% for [(±45) 5 ] s . The failure mode changed from fiber‐dominated brittle fracture to matrix‐dominated ductile failure between 15° and 20°. Discontinuous fibers weakened tensile properties, but this effect diminished at larger fiber angles. The pseudo‐ductility originated from the coupled effects of fiber reorientation, matrix plasticity, and interfacial damage.