Two-dimensional scattering features of the mixed second harmonic A0 mode Lamb waves for incipient damage localization

Area of Science:

• Materials Science
• Structural Health Monitoring
• Nonlinear Acoustics

Background:

• Detecting incipient structural damage is crucial for safety and maintenance.
• Nonlinear guided waves show promise for damage detection but struggle with localization.
• Previous research identified second harmonic A0 mode Lamb waves from wave mixing.

Purpose of the Study:

• To develop a two-dimensional damage localization method using nonlinear wave phenomena.
• To investigate damage-induced nonlinear wave scattering features.
• To validate the proposed localization method experimentally.

Main Methods:

• Utilizing second harmonic A0 mode Lamb waves generated through wave mixing.
• Visualizing the nonlinear wave field to study scattering features.
• Developing and evaluating a dedicated localization algorithm based on scattered wave energy distribution.

Main Results:

• Damage-induced nonlinear wave scattering energy is confined to a narrow region along the actuator-damage path.
• The spatial variation of scattered wave energy can be approximated by a Gaussian function.
• The proposed localization strategy successfully achieved damage localization in numerical simulations and experiments.

Conclusions:

• The newly discovered second harmonic A0 wave phenomenon enables effective two-dimensional damage localization.
• The proposed method offers a promising approach for structural health monitoring.
• Experimental validation confirms the efficacy of the nonlinear wave scattering features and localization algorithm.