Damage development under compression-compression fatigue loading in a stitched uniwoven graphite/epoxy composite material. Interim Report No. 86

Technical Report · Mon Jul 01 00:00:00 EDT 1991

OSTI ID:5203166

Vandermey, N E; Morris, D H; Masters, J E

Damage initiation and growth under compression-compression fatigue loading were investigated for a stitched uniweave material system with an underlying AS4/3501-6 quasi-isotropic layup. Performance of unnotched specimens having stitch rows at either 0 degree or 90 degrees to the loading direction was compared. Special attention was given to the effects of stitching related manufacturing defects. Damage evaluation techniques included edge replication, stiffness monitoring, x-ray radiography, residual compressive strength, and laminate sectioning. It was found that the manufacturing defect of inclined stitches had the greatest adverse effect on material performance. Zero degree and 90 degree specimen performances were generally the same. While the stitches were the source of damage initiation, they also slowed damage propagation both along the length and across the width and affected through-the-thickness damage growth. A pinched layer zone formed by the stitches particularly affected damage initiation and growth. The compressive failure mode was transverse shear for all specimens, both in static compression and fatigue cycling effects.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)
• OSTI ID: 5203166
• Report Number(s): N-91-28292; NASA-CR-188693; NAS-1.26:188693; CCMS-91-16; VPI-E-91-14; CNN: NAG1-343
• Resource Relation: Other Information: Interim Report No. 86
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
COMPRESSIBILITY
CRACK PROPAGATION
DAMAGE
DEFECTS
EPOXIDES
FAILURE MODE ANALYSIS
GRAPHITE
LAYERS
CARBON
ELEMENTAL MINERALS
ELEMENTS
MATERIALS
MECHANICAL PROPERTIES
MINERALS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
360603* - Materials- Properties