Damage development under compression-compression fatigue loading in a stitched uniwoven graphite/epoxy composite material

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° or 90° 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. 0° and 90° 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 compression failure mode was transverse shear for all specimens, both in static compression and fatigue cycling tests. Specimens without stitches were not available for comparison.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Engineering Mechanics

Department dc:contributor.department

Engineering Mechanics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1991

Author dc:creator

• Vandermey, Nancy E.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-10242009-020345

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/45318