Higher order acoustoelastic Lamb wave propagation in stressed plates

Area of Science:

• Materials Science
• Acoustics
• Solid Mechanics

Background:

• Lamb wave propagation is influenced by applied stress.
• Acoustoelasticity describes stress-induced changes in wave velocity.
• Industrial stress monitoring requires sensitive, non-destructive techniques.

Purpose of the Study:

• To investigate Lamb wave propagation perpendicular to applied stress.
• To determine the sensitivity of symmetrical and anti-symmetrical Lamb modes to stress.
• To evaluate the potential of higher-order Lamb modes for industrial stress measurement.

Main Methods:

• Developed analytical models and codes for wave dispersion curves in loaded plates.
• Conducted experiments using compression wave transducers on an aluminum plate.
• Applied uniaxial loads and measured strain using strain gauges.

Main Results:

• Model results and experimental data showed good agreement.
• The S1 mode of Lamb waves exhibited approximately ten times greater sensitivity to stress-induced velocity changes compared to bulk waves and fundamental Lamb modes.
• Higher-order Lamb modes demonstrated significantly enhanced sensitivity due to the acoustoelastic effect.

Conclusions:

• Higher-order Lamb modes offer superior sensitivity for stress measurement in plates.
• The findings support the potential use of these modes for online industrial stress monitoring.
• The enhanced sensitivity presents opportunities for developing improved stress measurement systems.