Towards an Alternative to Time of Flight Diffraction Using Instantaneous Phase Coherence Imaging for Characterization...

Area of Science:

• Non-destructive testing
• Ultrasonic phased array imaging
• Materials science

Background:

• Time of Flight Diffraction (TOFD) is a standard non-destructive testing (NDT) method for weld inspection.
• Ultrasonic phased array (UPA) imaging has advanced with algorithms like Total Focusing Method (TFM).
• Current TFM methods often rely on signal amplitude for imaging.

Purpose of the Study:

• To introduce and evaluate a novel Total Focusing Method (TFM) implementation using coherent summation of instantaneous signal phase.
• To compare the defect sizing and localization capabilities of this phase-based TFM with conventional TOFD.
• To assess the potential of phase-based imaging for automated ultrasonic testing (AUT).

Main Methods:

• Implementation of a TFM algorithm based on coherent summation of instantaneous signal phase.
• Experimental testing on steel samples with artificial crack-like defects.
• Comparative analysis of phase-based imaging and TOFD for defect characterization.

Main Results:

• The phase-based TFM demonstrated comparable defect sizing and localization to TOFD.
• Both methods effectively characterized defects without relying on signal amplitude.
• The proposed phase-based method generated easily interpretable images, aiding defect localization.

Conclusions:

• Phase-based TFM is a viable alternative to TOFD for weld inspection, offering similar characterization performance.
• The technique's ability to produce clear, interpretable images enhances defect localization.
• This approach holds significant promise for advancing automated ultrasonic testing (AUT).