A Novel Baseline-Free Method for Damage Localization Using Guided Waves Based on Hyperbola Imaging Algorithm.

Area of Science:

• Materials Science
• Mechanical Engineering
• Non-Destructive Testing

Background:

• Structural Health Monitoring (SHM) typically relies on reference signals from intact structures.
• Existing Lamb wave imaging methods often require baseline data, limiting their applicability.
• Damage detection and localization are critical for ensuring structural integrity.

Purpose of the Study:

• To develop and validate a novel baseline-free method for damage localization using ultrasonic Lamb waves.
• To implement a hyperbolic algorithm with a specialized transducer array for damage imaging.
• To assess the method's effectiveness in identifying through-thickness holes in plate structures.

Main Methods:

• A novel baseline-free hyperbolic algorithm was employed for damage localization.
• A symmetrical transducer array was designed to eliminate direct waves and utilize damage-scattered waves.
• Time-of-flight differences were calculated using cross-correlation of received signals.
• Numerical simulations and experimental measurements were conducted on an aluminum plate.

Main Results:

• The proposed method successfully localized damage (through-thickness hole) in an aluminum plate.
• Both internal and external damages relative to the array were detectable.
• Positioning accuracy was influenced by array size, with smaller arrays showing maximum error.
• The baseline-free approach demonstrated effective damage identification without prior structural data.

Conclusions:

• The developed hyperbolic algorithm offers a viable baseline-free approach for Lamb wave-based damage localization.
• The symmetrical array design effectively utilizes scattered waves for damage imaging.
• The method shows promise for real-world structural health monitoring applications where baseline data is unavailable.