Accession Number : ADA301222

Title :   Abrasion Behavior of Aluminum and Composite Skin Coupons, Stiffened Skins, and Stiffened Panels Representative of Transport Airplane Structures.

Descriptive Note : Technical paper,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CEN TER

Personal Author(s) : Jackson, Karen E.

PDF Url : ADA301222

Report Date : NOV 1985

Pagination or Media Count : 34

Abstract : A three-phase investigation was conducted to determine the friction and wear behavior of aluminum and composite materials under conditions similar to the loadings experienced by skin panels on the underside of a transport airplane during an emergency belly landing. In the first set of experiments, small skin coupons of aluminum and graphite-epoxy (Gr-Ep) were abraded in the laboratory. An abrasion test apparatus was designed which used a standard belt sander to provide the sliding surface. The test rig was equipped with a load cell to measure the frictional forces developed during abrasion. The skin-coupon specimens were abraded over a range of pressures (2 to 5 psi), belt velocities (16 to 50 mph), and belt surface textures (0.01 to 0.02 in.). The parameters chosen fall within the range of conditions considered typical of an airframe sliding on a runway surface. The effects of pressure and velocity on the wear rate and coefficient of dynamic friction were determined, and comparisons were made between the Gr-Ep and aluminum. Results of the laboratory tests indicate that Gr-Ep skin coupons have wear rates four to five times higher than aluminum and a coefficient of friction of about half that of aluminum. The second phase of the investigation involved abrading more representative skin structures, consisting of I-beams with attached skins constructed of aluminum, Gr-Ep, and glass hybrid composite. These stiffened skins were abraded on an actual runway surface over the same range of pressures and velocities as in the laboratory skin-coupon tests.

Descriptors :   *COMPOSITE MATERIALS, *SURFACES, *TRANSPORT AIRCRAFT, *FRICTION, *ABRASION, VELOCITY, MEASUREMENT, LABORATORY TESTS, ALUMINUM ALLOYS, DYNAMICS, PANELS, STIFFENING, RATES, TEST EQUIPMENT, GLASS, COEFFICIENTS, PRESSURE, AIRFRAMES, HYBRID SYSTEMS, BEHAVIOR, RUNWAYS, TEXTURE, SKIN(STRUCTURAL), SKIN FRICTION, GRAPHITE EPOXY COMPOSITES, SLIDING FRICTION, LANDING, LOAD CELLS.

Subject Categories : Transport Aircraft
      Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE