Numerical investigation of coupled intralaminar and interlaminar damage in toughened CFRP laminates subjected to low-velocity impact

Carbon fibre reinforced polymer (CFRP) laminates are widely used in lightweight structural applications because of their excellent strength-to-weight ratio. Despite these advantages, CFRP structures are particularly susceptible to barely visible damage when subjected to low-velocity impact. Such damage often results from complex interactions between intralaminar matrix cracking and interlaminar delamination, a problem that becomes more pronounced in laminates incorporating particle-toughened interlayers. Although many numerical studies have examined impact damage in composite materials, most existing models focus on conventional laminates and do not adequately represent the coupled intralaminar–interlaminar damage behaviour associated with toughened interlayers. In this study, a numerical framework is developed to examine the progressive damage behaviour of CFRP laminates with toughened interlayers under low-velocity impact loading. A finite element model is implemented in ABAQUS/Explicit, combining Hashin’s intralaminar failure criteria with cohesive zone modelling to simulate both interlaminar delamination and intralaminar damage. The impact responses of unidirectional and cross-ply laminates are investigated using spherical, conical, and flat impactors with identical mass and material properties. Model validation is carried out by comparing displacement–time responses with published numerical data, showing good agreement. The results demonstrate that both laminate configuration and impactor geometry play a significant role in governing deformation, stress distribution, and damage development. Cross-ply laminates exhibit higher stress concentrations due to ply orientation mismatch, whereas unidirectional laminates show better load-carrying capability. Matrix-dominated damage, particularly compressive matrix failure, is identified as the dominant failure mode across all impact conditions. In addition, flat and spherical impactors produce greater displacement and more severe damage than conical impactors as a result of their larger contact areas. Overall, the proposed framework provides clearer insight into the coupled damage mechanisms of toughened CFRP laminates and offers practical guidance for designing impact-resistant composite structures in aerospace and automotive applications.