Classification of Sound/Defective Region of Type 3 Composite Pressure Vessels Through Signal Post-processing in Ultrasonic Testing

This study aimed to distinguish between sound and defective areas in Type 3 composite pressure vessels. Ultrasonic testing was employed to detect artificially inserted defects. A 2D matrix array transducer was used for ultrasonic testing, and various parameters were adjusted. However, the signals observed in the A-scan could not clearly distinguish between intact and defective regions. To address this issue, a histogram transformation method was applied to postprocess the A-scan signals. A histogram was generated by selecting a specific area in the C-scan Time-of-Flight (TOF) image. The generated histograms had a U-shape in flawless regions whereas distinct histogram patterns were observed in the defective regions. This indicates that the histograms in the intact and defective regions are distinctly shaped, enabling effective differentiation between the two.