A Crack Size Quantification Method Using High-Resolution Lamb Waves.

Area of Science:

• Materials Science
• Non-Destructive Testing
• Wave Propagation

Background:

• Traditional tone burst excitation limits resolution in Lamb wave-based structural health monitoring.
• Signal processing challenges arise from prolonged received signals compared to excitation duration.

Purpose of the Study:

• To develop an advanced methodology for crack quantification using optimized Lamb wave excitation and signal processing.
• To enhance inspection resolution in plate-like structures for accurate damage assessment.

Main Methods:

• Utilized linear chirp (L-Chirp) and Golay complementary code (GCC) signals as Lamb wave excitation.
• Implemented pulse compression techniques for dispersion removal and resolution enhancement.
• Employed Abaqus CAE for simulations of healthy and cracked plates with varying damage sizes.
• Extracted damage features from the S0 mode wave package post-pulse compression.
• Developed a multivariate regression model to correlate damage features with crack size.

Main Results:

• The proposed method, using L-Chirp and GCC signals, demonstrated superior inspection resolution compared to traditional tone burst excitation.
• Simulations and validation experiments confirmed the effectiveness of the pulse compression approach.
• The multivariate regression model accurately correlated extracted damage features to crack dimensions.

Conclusions:

• High-resolution Lamb wave excitation, particularly with L-Chirp and GCC signals and pulse compression, offers a significant improvement for crack quantification.
• The developed methodology provides an accurate and effective means for assessing crack sizes in plate-like structures.