A Multi-Strategy Hybrid Sparse Reconstruction Method Based on Spatial-Temporal Sparse Wave Number Analysis for...

Area of Science:

• Non-destructive testing
• Wave propagation in solids
• Signal processing

Background:

• Ultrasonic guided waves (UGWs) are effective for detecting pipe defects.
• Coherent noise from dispersion, mode conversion, and imperfect detection limits UGW imaging performance.
• Accurate anomaly imaging requires overcoming these noise-related challenges.

Purpose of the Study:

• To propose a novel method for high-resolution and accurate anomaly imaging in defective pipes using UGWs.
• To address the limitations imposed by coherent noise in UGW-based defect detection.
• To enhance the performance of UGW testing for structural health monitoring.

Main Methods:

• Development of a multi-strategy hybrid sparse reconstruction (MHSR) method.
• Integration of spatial-temporal sparse wavenumber analysis (ST-SWA) for extracting wavenumber dispersion curves.
• Application of dispersion compensation to mitigate coherent noise effects.
• Sparse reconstruction imaging using compensated signals.

Main Results:

• The proposed MHSR method significantly enhances anomaly imaging in defective steel pipes.
• Improved defect resolution and positioning accuracy were demonstrated through experimental validation.
• Lowest estimated errors for axial and circumferential defect positions achieved were 10 mm and 4 mm, respectively.

Conclusions:

• The MHSR method, utilizing ST-SWA, effectively extracts dispersion curves for precise defect localization.
• Dispersion compensation within MHSR successfully mitigates coherent noise, improving imaging quality.
• The validated method offers a promising approach for accurate structural integrity assessment of pipes.