Publications

The behavior of carbon fiber-epoxy based aircraft composite materials in unmitigated fires

Brown, Alexander L.; Dodd, Amanda B.; Erickson, Kenneth L.

New aircraft are being designed with increasing quantities of composite materials used in their construction. Different from the more traditional metals, composites have a higher propensity to burn. This presents a challenge to transportation safety analyses, as the aircraft structure now represents an additional fuel source involved in the fire scenario. Performance testing data for composites burning in a fire at the integral scales of an accident event are nearly non-existent. This report describes fire tests for relevant carbon fiber epoxy materials that were designed to explore the bulk decomposition behavior of said material in a severe fire. Together with TGA decomposition data, the material is found to decompose in three mostly distinctive and sequential phases, epoxy pyrolysis, char oxidation, and carbon fiber oxidation. Fires were not severe in their thermal intensity compared to liquid fuel fires. Peak thermal intensities of around 220 kW/m2 or 1100 °C are achieved at very low air flow rates. The burn tests were remarkable in their duration, lasting 4-8 hours for 25-40 kg of combustible material.