Abstract

Failure mechanisms of graphite-fabric reinforced epoxy composites loaded in flexure have been studied, following ageing in dry, wet and hot environments. Experimental results based on mechanical loading to failure, dynamic mechanical analysis, electron microscopy and infrared spectra indicated that in the case of high temperature ageing in dry conditions the failure mechanism is characterized by shear at short loading spans and by tension at long spans. This failure mode changes to shear delamination after long duration ageing. Wet environments up to 50°C hardly affected the mechanical properties and failure mechanisms compared to those at ambient conditions. However, a reduction in the glass transition temperature was noticeable. Ageing in boiling water was harmful to the 120°C curing composite which was based on a dicyandiamide cured epoxy. Leaching of partially reacted components of the dicyandiamide epoxy system resulted in void formation, a considerable drop in mechanical properties and a change in the failure mechanisms. Enhanced hygrothermal stability of the 120°C dicyandiamide cured system was achieved by curing or post curing at 175°C.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.