Accession Number : ADA016959

Title :   Improving the Impact and Fracture Resistance of Fibrous Composites.

Descriptive Note : Final technical rept. Aug 74-Aug 75,

Corporate Author : CAMBRIDGE UNIV (ENGLAND) DEPT OF ENGINEERING

Personal Author(s) : Beaumont,Peter W. R. ; Martin,Vivien

Report Date : AUG 1975

Pagination or Media Count : 44

Abstract : A three phase program to improve the impact resistance of composite materials was undertaken. In the first phase, the Charpy impact test is investigated as a method for characterising dynamic behavior. The importance of differentiating between the energies of crack initiation and crack propagation is discussed, and a parameter called the Ductility Index is proposed, together with maximum stress and work of fracture for comparing the dynamic fracture behavior of fiber composites. Slow three point bending and instrumented impact tests were carried out to investigate the quasi-static and dynamic fracture behavior of (1) unidirectional fiber composites consisting of carbon and glass fibers embedded in an epoxy resin matrix; (2) cross-ply carbon fiber-reinforced epoxy resin composites, and (3) a carbon fiber/glass fiber/epoxy resin hybrid composite. It was found that fiber hybridization could raise both the fracture stress and toughness, and ductility index of carbon fiber composite materials.

Descriptors :   *REINFORCED PLASTICS, *FIBER REINFORCED COMPOSITES, *FRACTURE(MECHANICS), *IMPACT STRENGTH, CHARPY IMPACT TESTS, DYNAMIC TESTS, FLEXURAL STRENGTH, CRACK PROPAGATION, ALIGNMENT, DUCTILITY, CARBON FIBERS, FIBERGLASS, EPOXY RESINS, TEMPERATURE, GREAT BRITAIN

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE