A radar transducer for unidirectionally emitting and steering SH guided wave

Area of Science:

• Materials Science
• Mechanical Engineering
• Wave Physics

Background:

• Structural health monitoring (SHM) requires efficient methods for emitting, focusing, and steering wave modes.
• Traditional 2D phased arrays for SHM are complex, costly, and require numerous elements and electronics.
• Unidirectional wave emission and beam steering are crucial for rapid structural scanning in SHM.

Purpose of the Study:

• To propose and validate a novel radar transducer (RD-T) for unidirectionally emitting and steering the fundamental shear horizontal wave (SH0 wave).
• To demonstrate the RD-T's capability for efficient structural health monitoring and damage detection.

Main Methods:

• Design of an RD-T comprising an annular metasubstrate and rectangular piezoelectric wafers (d15).
• Theoretical modeling of SH0 wavefields and analysis of dimension parameter effects.
• Finite element simulations and experimental validation of the RD-T's performance, including beam steering and damage detection via pulse-echo experiments.

Main Results:

• The RD-T successfully achieves unidirectional emission and steering of SH0 waves between 200 kHz and 270 kHz with a high signal-to-noise ratio (SNR).
• Simulated and experimental results confirm the RD-T's ability to steer the wave beam in various directions.
• The RD-T effectively distinguishes symmetric defects and locates flaws with acceptable accuracy in pulse-echo tests.

Conclusions:

• The proposed RD-T offers an efficient alternative to 2D phased arrays for SHM, enabling 360° structural scanning.
• The RD-T's design simplifies electronics requirements by eliminating the need for extra time delays for driving.
• The RD-T demonstrates significant potential for advanced applications in structural health monitoring.