Measurement of ultrasonic wave mode transition in unidirectional graphite/epoxy composites

The wave propagation mechanism of mode transitions was studied in unidirectional composite materials. Theoretical calculations were compared with experimental measurements. Mode transitions occur when the wave vector orientation is varied in unidirectional samples of T300/5208 graphite/epoxy composite with a 0.6 fiber volume fraction. The mode transition occurs at 51.85° wave vector orientation with respect to the fiber direction. Energy flux deviation and particle displacement directions and amplitudes were also compared with theory. To show this mode transition, an attenuation study was performed. The attenuation coefficient, measured in units of reciprocal time, does not appear to depend on the wave vector orientation and the wave type (quasi-transverse and quasi-longitudinal waves) at 5 MHz frequency. But the attenuation coefficient, expressed in units of reciprocal length, does depend on the wave type and the wave vector orientation because the wave velocity is included in the calculation of this coefficient.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Materials Engineering

Department dc:contributor.department

Materials Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1991

Author dc:creator

• Vandenbossche, Benoit

Chair dc:contributor.committeechair

• Kriz, Ronald D.

Committee members dc:contributor.committeemember

• Gordon, Ronald S.
• Hendricks, Robert W.
• Henneke, Edmund G.

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-10242009-020340

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/45317