Accession Number : AD0851245

Title :   Characterizing Strength of Unidirectional Composites,

Corporate Author : MONSANTO RESEARCH CORP ST LOUIS MO

Personal Author(s) : Ishai, O. ; Lavengood, R. E.

Report Date : APR 1969

Pagination or Media Count : 33

Abstract : The report discusses a study to determine the effect of test variables on the strength of unidirectional composites. Specimens of glass fiber reinforced epoxy of varying geometry were tested in tension and flexure at several strain rates. Both experimental and theoretical results show that specimen geometry influences strength measurements for off-axis specimens having a small length to width ratio. This is a result of nonsymmetrical anisotropy in the specimens which causes twisting in flexure tests and shear coupling in tensile tests. For slender specimens, having a free length to width ratio greater than six both strength and stiffness measurements are almost unaffected by the boundary conditions of the test. A normalization procedure was successfully used to relate the strength of an off-axis composite to its transverse strength. While changes in loading mode, strain rate and specimen geometry may produce significant changes in absolute strength values, normalized strengths proved to be essentially invariant. (Author)

Descriptors :   (*COMPOSITE MATERIALS, MECHANICAL PROPERTIES), REINFORCED PLASTICS, EPOXY RESINS, GLASS TEXTILES, ANISOTROPY, LOADS(FORCES), TENSILE PROPERTIES, COMPRESSIVE PROPERTIES, BEAMS(STRUCTURAL).

Subject Categories : Laminates and Composite Materials
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE