Analysis of the directivity of Longitudinal Critically Refracted (LCR) waves

Area of Science:

• Materials Science
• Non-Destructive Testing
• Acoustics

Background:

• Longitudinal critically refracted (LCR) waves are used for near-surface material characterization, sensitive to stress but less to texture.
• Factors influencing LCR wave beam formation in experimental settings are not widely discussed.
• Optimization of LCR wave applications requires a deeper understanding of transducer parameter effects.

Purpose of the Study:

• To develop and present a novel numerical model for investigating transducer parameters affecting LCR wave directionality.
• To enable performance optimization of LCR waves in industrial applications through better understanding of beam formation.
• To identify critical transducer parameters that influence the characteristics of the LCR wave beam.

Main Methods:

• Development of a new numerical model to simulate LCR wave propagation and beam characteristics.
• Application of an orthogonal experimental method to systematically study the sensitivity of LCR wave parameters.
• Investigation of the effects of transducer aperture, center frequency, and incident angle on LCR wave directivity.

Main Results:

• The study demonstrates that transducer aperture, center frequency, and incident angle are the most significant factors controlling LCR wave field directivity.
• The numerical model was validated against finite element models and experimental data.
• The findings provide crucial insights into transducer selection and positioning for optimizing LCR wave experiments.

Conclusions:

• The developed numerical model enhances the understanding of LCR wave beam formation and directivity.
• Optimized transducer selection and positioning, guided by this model, can lead to improved LCR wave signals.
• This research facilitates higher sensitivity in near-surface stress characterization using LCR waves.