Accession Number : ADA301566

Title :   Mechanical Property Characterization of Intraply Hybrid Composites.

Descriptive Note : Technical memorandum,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

Personal Author(s) : Chamis, C. C. ; Lark, R. F. ; Sinclair, J. H.

PDF Url : ADA301566

Report Date : 03 OCT 1979

Pagination or Media Count : 29

Abstract : An investigation was conducted to characterize the mechanical properties of intraply hybrids made from graphite fiber/epoxy matrix (primary composites) hybridized with varying amounts of secondary composites made from S-glass or Kevlar 49 fibers. The tests were conducted using thin laminates having the same thickness. The specimens for these tests were instrumented with strain gages to determine stress-strain behavior. The results show that the mechanical properties of intraply hybrid composites can be measured using available test methods such as the ten-degree off-axis method for intralaminar shear, and conventional test methods for tensile, flexure, and Izod impact properties. Intraply hybrids have linear stress-strain curves to fracture for longitudinal tension and nonlinear stress-strain curves for intralaminar shear. The results also showed that combinations of high modulus graphite/S-glass/epoxy matrix composites exist which yield intraply hybrid laminates with the "best" balanced properties, for example: 100-percent increase in impact resistance, 35-percent increase in tensile and flexural strengths, with no reduction in modulus compared to graphite fiber/epoxy matrix composites. in addition, the results showed that the translation efficiency of mechanical properties from the consistituent composites to intraply hybrids may be assessed using a simple equation. (MM)

Descriptors :   *LAMINATES, *FIBER REINFORCED COMPOSITES, STRESS STRAIN RELATIONS, MECHANICAL PROPERTIES, TENSILE STRENGTH, IMPACT, COMPOSITE MATERIALS, FINITE ELEMENT ANALYSIS, STIFFNESS, CRACKING(FRACTURING), GRAPHITE, CARBON FIBERS, TOUGHNESS, MATRIX MATERIALS, BENDING, STRENGTH(MECHANICS), IMPACT STRENGTH, CRACK PROPAGATION, GLASS FIBERS, FLEXURAL STRENGTH, STRAIN GAGES, FATIGUE(MECHANICS), EPOXY COMPOSITES, MICROMECHANICS, FLEXURAL PROPERTIES, GRAPHITE EPOXY COMPOSITES, PROPELLERS, HYBRIDIZATION.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE