Numerical Investigation of Gaps and Overlaps in Variable Stiffness Composites Using Alternative Defect Modeling Approaches

This study examines the structural response of Variable Stiffness (VS) composite laminates manufactured by Automated Fiber Placement (AFP), focusing on the effects of gaps and overlaps on buckling and post-buckling damage initiation. To evaluate the performance of commonly used (DLM) and pixelated finite element methods, this work proposes the domain discretization approach as a benchmark that explicitly distinguishes defective and defect-free regions. The comparative analysis reveals that the DLM is highly efficient for capturing global phenomena like buckling but is unable to detect critical damage initiation occurring within the gap region. The pixelation method provides a satisfactory prediction of damage initiation with a higher computational cost due to the required fine mesh. These findings highlight the strengths and limitations of the examined defect modeling approaches, emphasizing the importance of selecting an approach aligned with the targeted structural phenomenon of interest.