Economics of Composites by Bullen George;Day Dan;Champa David;Hiken Alan;Grant Carroll;

Author:Bullen, George;Day, Dan;Champa, David;Hiken, Alan;Grant, Carroll;
Language: eng
Format: epub
ISBN: 9780768082340
Publisher: SAE International

The fire was one of three that the US Air Force studied “to identify new tools and techniques that will allow firefighters to more efficiently cut, penetrate, and extinguish burning aircraft made of composite materials.”

Such fires are challenging because hidden interior fires are difficult to extinguish, composites smolder and reignite, and fuselage penetration is virtually impossible with an axe and difficult with a K-12 (fire-fighting saw). The same difficulties would complicate the extraction of victims of crashes where composites were used as the material to construct the bodies of transportation vehicles.

In addition, the smoldering composite vehicle emits toxic smoke that may be harmful to rescue workers, witnesses, and bystanders. The physical and chemical properties of the particulate fraction of carbon-graphite/epoxy advanced composite material (cgeACM) smoke were measured to address concerns regarding potential health hazards posed by the release of fibers during pyrolysis of this material. Filter, low-pressure cascade impactor, and electrostatic precipitator samples were collected from cgeACM smoke in which the aerosol concentration ranged from 0.20 to 5.39 g/m3. Fibers were found in the smoke among individual, spherical, or nearly spherical particles and chain aggregates. The fibers had a mean count diameter of 0.54 micron and an average length of 2.84 microns. However, fibers accounted for approximately 0.3% of the particles counted. The smoke aerosols (including fibers) had mass median aerodynamic diameters (MMAD) ranging from 1.4 to 1.9 microns with standard geometric deviations ranging from 1.6 to 1.8, and hence more than 88% of the particles were in the thoracic size range (MMAD < or = 4.0 microns). All particles were composed primarily of carbon, silicon, sulfur, and oxygen with traces of other metals. By comparison fibers were composed almost exclusively of silicon. [6-6]

Asiana Airlines Flight 214 wreckage was strewn along Runway 28L at San Francisco International Airport after it crashed on July 6, 2013. The tail section had been torn from the wide-body Boeing (BA) 777 during the ill-fated landing. One of the huge engines was ripped from the aircraft's wings. The fire eventually incinerated the aircraft's core with such intensity that it burned through much of the roof. A gaping gash atop the fuselage revealed a fire-gutted interior from the conflagration that engulfed the airliner soon after it came to rest next to the tarmac. Figure 6.9 shows Asiana Airlines Flight 214 as it burns after the crash at San Francisco International Airport.

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