Lamb wave imaging via dual-frequency fusion for grating lobe effect compensation

Area of Science:

• Non-destructive testing
• Ultrasonic imaging
• Phased array techniques

Background:

• Lamb wave imaging using phased arrays offers precise damage detection.
• Element spacing in transducer arrays can exceed half the excitation wavelength, causing grating lobes.
• Grating lobes introduce artifacts and distortions in imaging results.

Purpose of the Study:

• To propose a novel Lamb wave imaging method for grating lobe effect compensation.
• To enhance the accuracy and quality of damage detection in phased array systems.
• To mitigate artifacts caused by grating lobes in ultrasonic imaging.

Main Methods:

• A dual-frequency fusion imaging method is developed.
• Two narrowband excitation pulses at different frequencies are utilized.
• Image results from both frequencies are fused to compensate for artifacts.

Main Results:

• The dual-frequency fusion method effectively compensates for grating lobe artifacts.
• Simulations and experiments on an aluminum plate validate the method's performance.
• Superior accuracy, contrast, and overall imaging quality are achieved.

Conclusions:

• The proposed dual-frequency fusion method is a viable solution for grating lobe compensation in Lamb wave imaging.
• This technique significantly improves the reliability and precision of damage detection.
• The method offers enhanced performance for phased array-based non-destructive evaluation.