Date of Award
Electrical and Computer Engineering
Applied sciences, Pure sciences
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Inline spot weld analysis (ISWA) is a relatively new application of ultrasonic technology that is capable of assessing spot welds as they are made. In previous studies, the fundamental concepts of ISWA have been uncovered and strong correlations with other test methods have been produced. Unfortunately, the current apparatus for ISWA has a low signal to noise ratio (SNR) in some installations which can lead to unusable weld signatures and incorrect interpretations. This work applies coded ultrasonic signals to ISWA in an attempt to improve the SNR of the acquired weld signatures and Ultimately improve the reliability of ISWA.
In this work, the apparatus for ISWA is modified to allow for the transmission of chirp encoded ultrasonic signals. The chirp signal that provides the best results with the modified apparatus is found and its scans are compared to scans obtained with the original apparatus. Overall, the scans taken with the original apparatus tend to have better contrast and less noise but the scans taken using the modified apparatus were similar in quality. However, the available equipment severely limited the amplitude of the chirp pulse so the fact that scans of similar quality were generated is impressive.
Barsanti, Lawrence, "Encoding ultrasonic signals to improve the signal to noise ratio for the inline inspection of spot welds" (2009). Electronic Theses and Dissertations. 7935.