Colloquium: Luca Alexander Baak (ASM)

This thesis investigates the effects of hygrothermal aging on the mode I and mode II fracture toughness of flax fiber-reinforced polymer composites (FFRP) under quasi-static and fatigue loading conditions. FFRP composites, offer a potential alternative to synthetic fibers, with environmental advantages but are vulnerable to environmental factors like temperature and humidity. Mode I and II delamination tests using Double Cantilever Beam (DCB) and End-Loaded Split (ELS) specimens revealed that hygrothermal aging impacts fracture toughness differently depending on loading conditions. The study found that one aging cycle enhanced mode I quasi-static toughness, but further aging cycles did not increase toughness, while mode II toughness remained unaffected. Fatigue tests, indicated a decrease in toughness after aging. These findings provide valuable insights for the design of FFRP and other biofiber composites, contributing to the development of more sustainable materials

Supervisor: John-Alan Pascoe, Yasmine Mosleh