Accession Number : ADA304703

Title :   Fracture Toughness of Fibrous Composite Materials.

Descriptive Note : Technical rept.,

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

Personal Author(s) : Poe, C. C., Jr

PDF Url : ADA304703

Report Date : NOV 1984

Pagination or Media Count : 69

Abstract : Laminates with various proportions of 0 deg, + or - 45 deg, and 90 deg plies were fabricated from T300/5208 and T300/BP-907 graphite/epoxy prepreg tape material. The fracture toughness of each laminate orientation or lay-up was determined by testing center-cracked specimens, and it was also predicted with the general fracture-toughness parameter. The predictions were good except when crack-tip splitting was large, at which time the toughness and strengths tended to be underpredicted. By using predictions, a parametric study was also made of factors that influence fracture toughness. Fiber and matrix properties as well as lay-up were investigated. Without crack-tip splitting, fracture toughness increases in proportion to fiber strength and fiber volume fraction, increases linearly with E22/E11, is largest when the modulus of non-0 deg fibers is greater than that of O deg fibers. (MM)

Descriptors :   *FIBER REINFORCED COMPOSITES, *TOUGHNESS, TENSILE STRENGTH, STRESS ANALYSIS, LAMINATES, STIFFNESS, MODULUS OF ELASTICITY, MATRIX MATERIALS, STRENGTH(MECHANICS), FRACTURE(MECHANICS), CRACK PROPAGATION, LIGHTWEIGHT, TAPES, FAILURE(MECHANICS), GRAPHITE EPOXY COMPOSITES, NOTCH SENSITIVITY.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE