Characterization of fracture toughness of epoxy resin after hygrothermal ageingGustavo Quino QuispeThe aim of this work is to characterize the e ects of hygrothermal aging in theplain strain fracture toughness of the epoxy system composed by cycloaliphatic epoxyresin and diglycidyl ether of bisphenol-A (DGEBA). For this, after having been underhygrothermal aging in a climatic chamber, epoxy samples were studied using ASTMD5045 fracture toughness test, and micrography and roughness measurements of thefracture surface. It is reported a rapid decrease of GIc and KIc during the rst 2 days.Moreover, a numerical model [13] was used to simulate and see with more detail thewater absorption in the aged samples. From that, it was observed the heterogeneousdistribution of water. Accordingly, it was proposed that the results should be correlatedwith the water content at the vicinity of the crack tip. Consequently, it waspossible to obtain, by quasi-static simulations, the ideal load-displacement curves ofcrack propagation in the heterogeneous samples. Finally, another contribution of thiswork is the study of the fracture surface, that gives a clue of the relationship amongthe fracture energy, the appearance of microcracks in the fracture surface, and theroughness (Ra).
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