ANALISI DELLO STATO TENSIONALE IN RESINE EPOSSIDICHE SOTTOPOSTE AD INVECCHIAMENTO IDROTERMICO MEDIANTE TECNICA FOTOELASTICA

[automatically translated] In this work, we analyzed the state of stress which arises in DGEBA epoxy systems when they are subjected to hydro-thermal aging, through the photoelastic technique in transmission, based on the method to change the phase of Tardy compensation. The specimens, monitored at regular time intervals during the processes of absorption and desorption of water, have been observed to circular polariscope. The technique has allowed to analyze both qualitatively and quantitatively, the stress state induced by the non-uniform "swelling" during the entire process of aging. In addition, the study also analyzed specimens criccati type Single Edge Notched Bending; the photoelastic analysis found that at the crack tip creates a peculiar photoelastic fringes system,