Investigation of the Effect of Resin Material on Impact Damage to Graphite/Epoxy Composites.

This report describes the results of an experimental program that establishes the feasibility and guide lines for new resins development. The objective was to identify the basic epoxy neat resin properties that will improve low velocity impact resistance and toughness to graphiteepoxy laminates and, at the same time, maintain useful structural laminate mechanical properties. Material tests from twenty-three toughened epoxy resin matrix systems are included in this investigation. The apparent desirable neat resin properties to obtain the best combination of impact and mechanical composite properties are tensile strength above 6.89xlO to the 7th Newtonssq m 10,000 psi,- tensile modulus above 3.lOx l0 to the 9th Newtonssq m 450,000 psi, and tensile elongation between 5 and 6. MM