Method for improving the accuracy of damage signal recognition based on the thickness-graded additional structure

Area of Science:

• Materials Science
• Mechanical Engineering
• Structural Health Monitoring

Background:

• Lamb wave-based damage identification is crucial for structural health monitoring.
• Boundary echoes in S0 mode Lamb waves hinder accurate damage localization.
• Existing methods for echo control are often limited in effectiveness.

Purpose of the Study:

• To propose and validate a novel thickness-gradient additional structure (TGAS) for controlling S0 mode Lamb wave boundary echoes.
• To investigate the mechanisms behind the echo suppression.
• To demonstrate the superiority of TGAS over conventional methods.

Main Methods:

• Numerical simulations were performed to analyze wave propagation and echo control.
• Dispersion curves of variable-thickness plates were analyzed.
• Displacement responses and power flow were studied to understand suppression mechanisms.
• A TGAS prototype was fabricated using wire-cutting technology for experimental validation.

Main Results:

• The TGAS demonstrated effective control of S0 mode Lamb wave boundary echoes over a wide frequency range.
• Analysis revealed the mechanisms responsible for boundary echo suppression.
• Experimental results confirmed the significant effectiveness of the TGAS.
• The TGAS showed a superior control effect compared to clay.

Conclusions:

• The proposed TGAS is a highly effective solution for mitigating boundary echo issues in S0 mode Lamb wave analysis.
• This advancement can significantly enhance the accuracy of Lamb wave-based damage identification techniques.
• TGAS offers a promising approach for improved structural health monitoring.