Impact localization on a metal plate using matched field processing and a microphone arraya)

Area of Science:

• Acoustics
• Structural Health Monitoring
• Signal Processing

Background:

• Acoustic waves are valuable for remote sensing and structural health monitoring due to their non-contact measurement capabilities.
• Traditional source localization methods struggle with complex geometries, wave dispersion in structures, and sensor contact issues.
• Impact source localization is a critical task in structural health monitoring.

Purpose of the Study:

• To adapt and apply Bartlett matched field processing (MFP) for localizing impact excitations on a metal plate.
• To evaluate the performance of MFP in a complex structural acoustics environment.
• To assess the robustness of MFP under noisy conditions.

Main Methods:

• Utilized a 14-microphone array to record acoustic waves radiated from an impacted aluminum plate.
• Employed Bartlett matched field processing (MFP), a technique from underwater acoustics.
• Integrated MFP with a physics-based finite-element acoustic environment model for localization.
• Investigated localization performance with varying signal-to-noise ratios.

Main Results:

• Impact sources were localized on a round aluminum plate with typical accuracy within 1.1 cm of the true location.
• The Bartlett matched field processing (MFP) method demonstrated successful localization down to a signal-to-noise ratio of -7.5 dB.
• Ambiguity surfaces were generated to visualize predicted source locations.

Conclusions:

• Bartlett matched field processing (MFP) is a viable and accurate technique for non-contact impact source localization in structural health monitoring.
• MFP offers advantages over traditional methods by accommodating complex structural acoustics and avoiding physical sensor contact.
• The developed method shows promise for real-world applications, including noisy environments.