Quantitative evaluation of crack based on the sparse decomposition of array Lamb wave propagation

Area of Science:

• Structural Health Monitoring
• Non-Destructive Testing
• Wave Mechanics

Background:

• Crack damage in engineering structures can lead to catastrophic failures, especially at stress concentration points.
• Lamb waves are sensitive to structural defects, offering a potential method for damage detection.

Purpose of the Study:

• To develop a novel approach for identifying crack location and size using Lamb wave reflections and diffractions.
• To analyze the interaction mechanism between Lamb waves and cracks to extract damage information.
• To visualize crack size and orientation without relying on baseline signals.

Main Methods:

• Analysis of Lamb wave reflections and diffractions interacting with cracks.
• Classification of wave signals into reflections and diffractions using a threshold.
• Construction of an overcomplete dictionary for waveform analysis.
• Application of sparse decomposition to map signals to propagation distances.
• Utilizing diffractions for crack tip identification and reflections for edge point information.

Main Results:

• The method successfully maps received signals to propagation distances without baseline data.
• Crack tip points are determined using diffractions, and edge points using reflections.
• Kinked crack size and orientation are visualized using time-domain signals.
• Numerical simulations and experimental data show high agreement with actual crack characteristics.

Conclusions:

• The proposed method effectively identifies crack location and size by analyzing Lamb wave interactions.
• The technique demonstrates high accuracy and efficacy in visualizing crack geometry.
• This approach offers a promising non-destructive evaluation tool for structural integrity assessment.