Accession Number : ADA325973

Title :   A Study on Fracture Toughness of Advanced Structural Composites,

Corporate Author : NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA

Personal Author(s) : Chang, George C.

PDF Url : ADA325973

Report Date : 31 JUL 1973

Pagination or Media Count : 113

Abstract : The basic concept of structural fracture in homogeneous, isotropic materials is discussed. Fundamental relationships associated with the linear elastic fracture mechanics, based on the Griffith Irwin approach, are presented. Discussed next are properties of fiber reinforced (or filamentary) composite materials from fracture mechanics point of view. Representative fracture test results are then reviewed and analyzed. Involved in the tests are numerous composites such as beryllium/aluminum, glass/epoxy, Scotchply, boron/aluminum, graphite/polyimide, etc. Some of these nonhomogeneous anisotropic composites are unidirectionally reinforced, while other are angle plied. Finally, the fracture phenomenon and process in filamentary composites are discussed in details. It is found that the linear elastic fracture mechanics is applicable to most composite materials which have been investigated. It is nevertheless premature and risky to predict the applicability of the theory to the filamentary composite materials in general. Also made in this report are recommendations for future work on fracture of structural composites intended for high performance flight vehicles.

Descriptors :   *AIRCRAFT, *CRACKING(FRACTURING), *FIBER REINFORCED COMPOSITES, *FRACTURE(MECHANICS), *GRAPHITE EPOXY COMPOSITES, ALUMINUM ALLOYS, STRUCTURAL PROPERTIES, ELASTIC PROPERTIES, GRAPHITE, TOUGHNESS, ISOTROPISM, LINEARITY, GLASS FIBERS, BERYLLIUM ALLOYS, POLYIMIDE PLASTICS, BORON ALLOYS.

Subject Categories : Laminates and Composite Materials
      Mechanics
      Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE