Accession Number : ADA307131

Title :   Techniques for the Measurement of the Flexural Rigidity of Thin Films and Laminates.

Descriptive Note : Technical note,

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

Personal Author(s) : Price, Howard L.

PDF Url : ADA307131

Report Date : APR 1966

Pagination or Media Count : 36

Abstract : A method of measuring the flexural rigidity of thin films and laminates is described. The method employs the principle of the heavy elastic a which relates flexural rigidity to the deflection of the material under its own weight. Results are presented of tests to determine the stiffness of plastic films and plastic-metal laminates for use in space structures experiments. Tests were performed on untreated and aluminized polyETHYLENE TEREPHTHALATEJ FILM, ALUMINUM FOIL, AND LAMINATES OF ALUMINUM FOIL AND POLYETHYLENE TEREPHTAHLATE film or polypropylene film. The thickness of the materials ranged from 0.00018 inch (0.00046 cm) to 0.00270 inch (0.00691 cm). The weight efficiency in flexure is presented, the efficiency of the aluminized polyETHYLENE TEREPHTHALATE film (Echo I material) being taken as unity. It has been shown that the principle of the heavy elastic a (including both the heart-loop and the cantilever methods) is valid for such determinations if the material does not have a static electric charge. Although higher stiffness can be obtained at the expense of more weight, the investigation showed that the rigidity can increase more rapidly than the weight. Compared with the Echo I material, the laminates had the highest efficiencies of the materials that were tested. A comparison between the flexural stiffness determined by a standard stiffness tester and that determined by the heavy-elastic a method revealed that the results of the two methods correlated well only for comparatively large values of stiffness. For small values, however, or for small differences in stiffness, the elastica method was the more sensitive method.

Descriptors :   *SPACECRAFT, *LAMINATES, *THIN FILMS, *PLASTICS, *FLEXURAL PROPERTIES, SPACE SYSTEMS, STIFFNESS, ELASTIC PROPERTIES, DEFLECTION, SENSITIVITY, POLYPROPYLENE, ALUMINUM, RIGIDITY, CANTILEVER BEAMS, STATIC ELECTRICITY, ALUMINUM FOIL, POLYETHYLENE, POLYETHYLENE TEREPHTHALATE.

Subject Categories : Laminates and Composite Materials
      Plastics
      Unmanned Spacecraft
      Manned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE