Mechanical response and critical failure mechanism characterization of notched carbon fiber reinforced polymer laminate subjected to tensile loading

The purpose of this article is to investigate the mechanical responses and critical failure mechanisms of notched composite laminates with the aid of numerical and experimental approaches, considering the effect of notch geometry, notch size and off-axis angle. Quasi-static tensile tests are implemented to study the influence of design variables on the mechanical response, during which the relationship of force vs displacement and strain distributions are collected by means of digital image correlation technique. Subsequently, the numerical simulation is implemented in ABAQUS/Explicit through a progressive damage model integrated with a VUMAT subroutine. Meanwhile, the initiation and propagation of damage are explored through the damage morphologies, combining with the logarithmic strain components from numerical predictions. Results show that notch strength and failure strain are more closely associated with off-axis angle and notch size compared with notch geometry. In addition, with the increase of off-axis angle, the contribution of fiber is increasingly weakened, the damage mode gradually varies from fiber fracture to pull out accompanied with the damage near the notch changing from fiber fracture to delamination. Meanwhile, the critical failure mechanism varies from tension dominated to tension-shear/shear dominated as the off-axis angle grows larger.