Mode I Fracture Toughness of Aerospace Polymer Composites Exposed to Fresh and Salt Water

Abstract

With the increasing use of polymer matrix composites (PMCs) in aircraft structures, there is a need to improve the understanding of the long-term environmental durability of these advanced materials. Unlike metals, where one of the primary mechanisms of degradation is corrosion, polymer composite structures are susceptible to environmental degradation in different ways. In order to better understand these effects, an investigation into the influence of temperature, humidity and salinity on Mode I fracture toughness of adhesively bonded joints in PMCs was carried out. The objective of this study was to build an improved understanding of composite degradation mechanisms that may affect long-term performance of composite structures. Double Cantilever Beam (DCB) specimens were manufactured by bonding carbon fibre/epoxy laminates with epoxy film adhesive and then exposed to seven different environmental conditions including. The Mode I strain energy release rate, G IC , was measured and the effect of different conditions on the disband behavior was identified.

High Temperature Nanoindentation Response of RTM6 Epoxy Resin at Different Strain Rates

“…Hygrothermal aging typically refers to the deterioration of the performance of a material due to prolonged exposure to moisture and variable temperature conditions (http://ntrs.nasa. gov/archive/nasa/casi.ntrs.nasa.gov/20090023547_ 2009022929.pdf) [3][4][5]. The ability to measure the local mechanical properties by nanoindentation would allow determining the hygrothermal aging suffered by the resin in real CFRP subjected to service conditions [6].…”