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原文传递 Flammability Properties of Aircraft Carbon-Fiber Structural Composite.

题名：	Flammability Properties of Aircraft Carbon-Fiber Structural Composite.
作者：	quintiere, j. g. walters, r. n. crowley, s.
关键词：	carbon fibers,composite materials,flammability testing,aircraft construction materials/aircraft fires, heat release, fire resistance materials, burning rate, thermal conductivity, heat flux, fire behavior/flame spread
摘要：	This study investigated the flammability of a carbon-fiber composite material for use in aircraft structures. In particular, it considered a composite material manufactured by Toray Composites (America) to Boeing Material Specification 8-276. The objective was to establish a complete set of properties pertaining to the heating and burning characteristics of these materials in fires. Several apparatuses were used, including the cone calorimeter, microscale combustion calorimeter, thermogravimetric analyzer, differential scanning calorimeter, and a flame spread rig to promote spread with preheating by radiation. An attempt was made to measure the thermal conductivity of the composite over a range of temperatures through its decomposition, but the heat losses from the apparatus likely caused an overestimate in the measurement. Data from standard tests were also reported for the Ohio State University calorimeter and the smoke density chamber. The material burns in a manner similar to a charring material, in that the carbon fibers comprise most of its mass. The composite burns primarily from the vaporization of its resin. It can ignite with a pilot flame after preheating at a low heat flux. When it burns, the resin vapor is forced out of the fiber pores, and pressure causes the material to swell to over twice its volume. In most all cases studied, the composite maintained its rigidity, but its structural strength was not examined after degradation. The material appears to maintain homogeneity in swelling. The fibers create an insulating, char-like structure that causes a reduction in the internal heating, and consequently, the burning rate drops in time. As the burning rate drops, extinction can naturally occur due to insufficient heating. As is common of charring materials, external heat flux is required to sustain burning and flame spread. It should be noted that the carbon fiber can also oxidize under high-temperature conditions, and this was observed even at low heat fluxes. / NOTE: Final rept. / Supplementary Notes: Prepared in cooperation with Maryland Univ., College Park. Dept. of Fire Protection Engineering. Sponsored by Federal Aviation Administration, Washington, DC. Aviation Research and Development. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5285 Port Royal Road, Springfield, VA, 22161, USA.
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