Fracture toughness evaluation of filament-wound carbon fiber laminates: case study

Zuzanna Pacholec, Karolina Paczkowska, Jakub Stolarczyk, Marcin Bogucki, Michał Barcikowski, Wojciech Błażejewski, Paweł Bury, Krzysztof Towarnicki, Paweł Stabla

Pre-print pages 1-27

DOI: https://doi.org/10.62753/ctp.2026.04.3.3

keywords: filament winding, interlaminar fracture toughness, delamination, carbon fiber-reinforced polymer (CFRP), mixed-mode fracture

abstract Filament-wound fiber-reinforced polymer (FRP) composites are widely used in pressure vessels and tubular structures; however, their interlaminar fracture behavior remains insufficiently understood. This study investigates the fracture toughness of helically wound carbon fiber-reinforced polymer (CFRP) laminates under mode I, mode II, and mixed-mode loading using DCB, ENF, and MMB tests. The results showed that the fracture behavior was strongly influenced by the fiber orientation, fiber cross-over regions, and void content in the composite structure. Fiber interlacing increased the resistance to crack propagation by forcing the crack front to follow a more complex path, while an increased void content reduced the local fracture resistance and promoted crack growth. The mixed-mode tests indicated that the fracture re-sistance grew with the contribution of mode I loading. The findings demonstrate that the wound laminate structure plays a key role in delamination development and should be considered in the design of filament-wound composite structures.