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1 August 2003 Development and testing of an automated acousto-ultrasonic scan system
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Acousto-ultrasonics (AU) is a NDE technique that utilizes two ultrasonic transducers to interrogate the condition of a test specimen. The sending transducer introduces an ultrasonic pulse at a point on the surface of the specimen while a receiving transducer detects the signal after it has passed through the material. The aim of the method is to correlate certain parameters of the detected waveform to characteristics of the material between the two transducers. The waveform parameter of interest is the attenuation due to internal damping for which information is being garnered from the frequency domain. The parameters used to indirectly quantify the attenuation are the ultrasonic decay rate as well as various moments of the frequency power spectrum. For the most part, AU is used to gage the damage state of materials subjected to various mechanical or environmental loads. The AU technique has been applied to polymer matrix composites, ceramic matrix composites, metal matrix composites as well as metallic alloys. Historically, AU has been a point by point, manual technique with waveforms collected at discrete locations and post-processed. Data collection and analysis of this type limits the amount of detail that can be obtained. Also, the manual movement of the sensors is prone to user error and is time consuming. This paper discusses an automated AU scanning system recently developed and assembled at NASA Glenn Research Center. The paper will include a description of the hardware and software systems as well as the techniques for data reduction and presentation. In order to demonstrate the system capabilities, AU scan results for a SiC/SiC composite panel are presented.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Richard E. Martin, Andrew L. Gyekenyesi, and Donald J. Roth "Development and testing of an automated acousto-ultrasonic scan system", Proc. SPIE 5046, Nondestructive Evaluation and Health Monitoring of Aerospace Materials and Composites II, (1 August 2003);

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