New materials and manufacturing processes, and the quest for economy and user safety, have necessitated the development of nondestructive testing methods to quantify the life and reliability of a product during manufacture and service. Described herein, is a testbed to be used in the research and development of these testing methods. A brief motivation for using ultrasonics applied to nondestructive evaluation is followed by a chapter on the feasibility of using a unique testing method and animated data presentation on advanced composite materials. This testing method, conceived by the author, utilizes oblique injection of ultrasound into the specimen. Several cycles of the ultrasonic waveform radiated from the specimen downstream of the injection area is digitized and recorded. The data has three independent dimensions; cartesion location and time. The time variable is the key to the presentation of the data as an animated two dimensional image. It was this work that illustrated the need for a flexible scanning imaging research testbed, not only for the discussed method, of which it is an integral part, but for advanced development of other techniques. Software development and integration of off -the-shelf parts into a unified computer controlled testing facility is the contribution by the author in the second phase of this research. Chapters on the description of the system, an example showing the capabilities of the system analogous to traditional ultasonic C-scanning, accomplishments, and a look to the future conclude this thesis. The appendices include listings of the programs developed for the system, a manufacturer address list. A videotape of the animation data presentation is included as a second volume of this thesis. / Master of Science

This thesis contains the results of Phase-1 of a project funded by Ford Motor Company. The objective is to study the feasibility of Acousto-Ultrasonics (AU) as a nondestructive technique for assuring the quality of adhesively bonded sheet-metal used for automobiles. Other nondestructive (NDT) techniques were also applied viz., ultrasonics. radiography and thermography to supplement and verify the results of the AU technique. The AU Technique demonstrated the best results in terms of its sensitivity to the variations in the properties of the interface. Regions having kissing bonds or regions lacking adhesive were easily identified by this technique. These regions contribute to the mixed mode failure. A bond quality (BQ) model is suggested to take into account the mixed mode failure. Destructive testing results show fairly consistent correlation of BQ values with the breaking strength of the adhesive joint failing in mixed mode failure. The BQ values were calculated from the SWF (stress wave factor) values generated by the AU technique. No correlation was observed between the SWF values and the breaking strengths of the bonds failing cohesively. Cohesive failures occur at higher loads than those for mixed mode failures. These are, of course, governed by the maximum possible strength of a joint. More work needs to be done to develop a better way to analyze signals for differentiating total cohesive failure, at least for academic interest. The results strongly suggest the potential of this technique for quantitative evaluation of such types of bonding. Automation of this technique can be developed for application on the assembly line of the motor-car industry. Future work to make this technique more efficient and sensitive is suggested. / Master of Science