Measurement of multiaxial ply strength by an off-axis flexure test

Conference · Sun Mar 01 00:00:00 EST 1992

OSTI ID:7237754

Crews, Jr, J H; Naik, R A

An off-axis flexure (OAF) test was performed to measure ply strength under multiaxial stress states. This test involves unidirectional off-axis specimens loaded in bending, using an apparatus that allows these anisotropic specimens to twist as well as flex without the complications of a resisting torque. A 3D finite element stress analysis verified that simple beam theory could be used to compute the specimen bending stresses at failure. Unidirectional graphite/epoxy specimens with fiber angles ranging from 90 deg to 15 deg have combined normal and shear stresses on their failure planes that are typical of 45 deg plies in structural laminates. Tests for a range of stress states with AS4/3501-6 specimens showed that both normal and shear stresses on the failure plane influenced cracking resistance. This OAF test may prove to be useful for generating data needed to predict ply cracking in composite structures and may also provide an approach for studying fiber-matrix interface failures under stress states typical of structures.

• Research Organization: National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center
• OSTI ID: 7237754
• Report Number(s): N-92-24880; NASA-TM-107570; NAS-1.15:107570; CONF-9205232-; CNN: RTOP 505-63-50
• Resource Relation: Conference: 11. American Society for Testing and Materials (ASTM) symposium on composite materials: testing and design, Pittsburgh, PA (United States), 4-5 May 1992
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON FIBERS
FLEXURAL STRENGTH
COMPOSITE MATERIALS
EPOXIDES
ANISOTROPY
BENDING
FAILURE MODE ANALYSIS
FINITE ELEMENT METHOD
GRAPHITE
INTERFACES
LAYERS
MATERIALS TESTING
MATRIX MATERIALS
MECHANICAL TESTS
PERFORMANCE
STRESS ANALYSIS
THREE-DIMENSIONAL CALCULATIONS
TORQUE
CARBON
DEFORMATION
ELEMENTAL MINERALS
ELEMENTS
FIBERS
MATERIALS
MECHANICAL PROPERTIES
MINERALS
NONMETALS
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
TESTING
360603* - Materials- Properties