Title page for ETD etd-05022009-040452
|Type of Document
||Karhnak, Stephen J.
||Predicting mechanical performance of adhesively bonded joints based on acousto-ultrasonic evaluation and geometric weighting
||Master of Science
|Duke, John C. Jr.
|Cramer, Mark S.
|Dillard, David A.
|Date of Defense
Prediction of the performance of adhesively bonded joints is essential to the acceptance
of this mode of fastening. In ideal situations where the bonding is uniform throughout
the joint the stress distribution depends on the material properties and the joint
geometry. Knowledge of the bond properties and the stress distribution and magnitude
can then be used to determine failure initiation, damage growth, subsequent stress
distributions, and final failure. However, few bonds can be characterized as "ideal", as
the bonding is generally not uniform throughout the joint and even the properties of the
adhesive may vary. This paper describes work that addresses this situation. Acoustic
microscopy has been used to provide a detailed image of the bonded joint, while
acousto-ultrasonic measurements have been used to evaluate the stress transfer
capability of modified lap shear joints. Knowledge of the stress distribution in the joint
has provided a means of identifying critical areas of interest in the joint. The
adhesively bonded composite specimens were mechanically tested and performance
correlated with NDE results. Wave mode filtering is offered as a phenomena
describing the basis for the correlation.
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