Impact damage and CAI strength of a woven CFRP material with fire retardant properties

This paper presents the interrogation of low velocity impact and compression after impact test results on a woven fibre composite having a fire retardant, syntactic core, two phase epoxy matrix. The results of the study were to be utilized in a decision making process regarding the appropriateness of the material usage in question for a certain aerospace application. The epoxy matrix of the material system had dispersed black-pigmented particles with flame-retarding properties. Impact tests were performed at five impact energy levels. Two different laminate layup configurations were tested. Visual and C-Scan inspection were conducted, in order to observe the extent of the damage in the composite material. Compression tests were performed to study the residual strength after impact. Analytical formulation correlations with the test results presented opportunities for quantifying the interfacial fracture toughness resistance. Micro-graphs of the specimen's cross section were also produced in an effort to observe the fractured sections and characterise the various fracture mechanisms involved. The results exploitation in terms of design decision making are presented.