<p dir="ltr">This work focuses on the fracture behavior and failure mechanisms of Prepreg Platelet Molded Composites (PPMCs), which are characterized by meso-structural variability. The study investigates the interlaminar fracture toughness of PPMCs using both experimental and computational approaches, with a particular focus on Mode-I fracture testing. Cohesive zone models are developed to simulate interfacial behavior in composite laminates. The research introduces the concept of the platelet critical length problem and explores how platelet geometry, arrangement, and meso-structural features affect fracture toughness and energy absorption. Findings indicate that smaller platelets enhance fracture toughness through mechanisms like platelet bridging and crack deflection, while larger platelets provide more consistent fracture properties but exhibit greater variability in stiffness. This work offers valuable insights for optimizing PPMC performance in high-performance applications.</p>