Results are presented on the interlaminar shear strength (ILSS) and Mode I fracture toughness (GIC) of glass/epoxy laminates interleaved with thermoplastic polyester films using four-point bending and double cantilever beam tests, respectively. The ILSS equation from classical beam theory was modified to account for the increased film thickness. It was found that the ultimate failure load and ILSS could be doubled if a thermoplastic film of high ductility but low glass transition temperature is used. Good film/composite ply adhesion is necessary. Mode I fracture toughness is influenced by film thickness and interleaving with a 0.2 mm thick film increased the GIC by 40 percent. Interleaving with a thinner film (0.1 mm), however, resulted in adhesive failure and reduced fibre bridging.
Issue Section:
Technical Papers
Topics:
Composite materials,
Fracture (Materials),
Fracture (Process),
Shear strength,
Failure,
Film thickness,
Fracture toughness,
Adhesion,
Adhesives,
Cantilever beams,
Diluents,
Ductility,
Epoxy adhesives,
Epoxy resins,
Euler-Bernoulli beam theory,
Fibers,
Glass,
Glass transition,
Laminates,
Polyester film,
Stress,
Thick films
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