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

Area of Science:

• Acoustics
• Structural Health Monitoring
• Signal Processing

Background:

• Traditional source localization methods face challenges with complex geometries and wave propagation in structural health monitoring.
• Accurate impact source localization is crucial for assessing structural integrity.

Purpose of the Study:

• To adapt Matched Field Processing (MFP), typically used in underwater acoustics, for localizing impact sources on metal plates using airborne sound.
• To evaluate the effectiveness of physics-based models in conjunction with MFP for this application.

Main Methods:

• Applied MFP to acoustic data from microphones measuring sound radiated by an impact on an aluminum plate.
• Developed and utilized physics-based finite element models (infinite and finite plates) to simulate acoustic wave propagation.
• Investigated localization accuracy under varying signal-to-noise ratios and model-data mismatches.

Main Results:

• Achieved localization errors within 0.5 cm using temporally trimmed data with both infinite and finite plate models.
• The finite plate model demonstrated over 80% localization accuracy down to -7.5 dB signal-to-noise ratio in noisy environments.
• MFP showed robustness to moderate source characterization mismatches but sensitivity to sensor location and plate thickness deviations.

Conclusions:

• Matched Field Processing is a viable technique for localizing impact sources on metal plates using remote acoustic measurements.
• Physics-based finite element modeling enhances localization accuracy, particularly when accounting for specific plate characteristics and edge effects.
• The study highlights MFP's potential for advanced structural health monitoring, with identified sensitivities to environmental and model parameters.