Ultrasonic wave propagation in thick, layered composites containing degraded interfaces

The ultrasonic wave propagation of thick, layered composites containing degraded bonds is investigated. A theoretical one-dimensional model of three attenuative viscoelastic layers containing two imperfect interfaces is introduced. Elastic material properties and measured 'values of ultrasonic phase velocity and attenuation are used to represent E-glass and vinyl ester resin fiber-reinforced plastic (FRP) laminate, syntactic foam, and resin putty materials in the model. The ultrasonic phase velocity in all three materials is shown to be essentially constant in the range of 1.0 to 5.0 megahertz (MHz). The attenuation in all three materials is constant or slightly increasing in the range 1.0 to 3.0 MHz. Numerical simulation of the model via the mass- spring-dashpot lattice model reveals the importance of the input signal shape, wave speed, and layer thickness on obtaining non-overlapping, distinct return signals in pulse-echo ultrasonic nondestructive evaluation. The effect of the interface contact quality on the reflection and transmission coefficients of degraded interfaces is observed in both the simulated and theoretical results.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Ocean Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Small, Peter D. (Peter David)

Advisor dc:contributor.advisor

• James H. Williams and David V. Burke.

• Ocean Engineering.
• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33585

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33585