Extraction of texture in metal sheet using non-contact electromagnetic acoustic transducers (EMATS) and wavelet processing Available to Purchase

EMATs have been used to generate ultrasonic Lamb wave for the characterization of texture in metal sheets. Ultrasonic techniques have received considerable attention as an alternative technology for monitoring the texture of metal sheet, and many of these studies used EMATs for ultrasonic generation and detection. In this study, a different approach to the analysis has been used. In the previous work, only three constants define the elastic anisotropy in the most commonly used approximation. These were measured typically at 0°, 45°, and 90° with respect to the metal sheet. However, greater accuracy in calculating these Orientation Distribution Coefficients (ODCs) values can potentially be obtained by fitting the theoretical angular dependent velocity to the experimental data. It is then possible to extract the ODCs and obtain some degree of confidence in the values from the correlation of the fit. In this study, this approach has been implemented in the presence of multiple Lamb modes generated and detected by the magnetostrictive type EMATs using the Stationary wavelet transform (SWT) to extract the required data from selected Lamb wave modes.