Experimental and numerical investigations on the acoustoelastic effect in hyperelastic waveguides

TL;DR

This study combines extensive experimental and numerical methods to analyze how pre-stress affects Lamb wave propagation in hyperelastic waveguides, validating models and revealing model-specific predictions for wave velocity changes.

Contribution

It provides a comprehensive validation of the Neo-Hooke and Murnaghan models against experimental data across a wide frequency range for the acoustoelastic effect.

Findings

Neo-Hooke model accurately predicts pre-stress effects in most cases.

Murnaghan model captures sign change in phase velocity for the $A_0$ mode at high frequencies.

Murnaghan model fails to predict sign change for the $S_0$ mode.

Abstract

Guided ultrasonic wave based structural health monitoring has been of interest over decades. However, the influence of pre-stress states on the propagation of Lamb waves in thin-walled structures is not fully covered, yet. So far experimental work presented in the literature only focuses on a few individual frequencies, which does not allow a comprehensive verification of the numerous numerical investigations. Furthermore, most work is based on the strain-energy density function by Murnaghan. To validate the common modeling approach and to investigate the suitability of other non-linear strain-energy density functions an extensive experimental and numerical investigation covering a large frequency range is presented here. The numerical simulation comprises the use of the Neo-Hooke as well as the Murnaghan material model. It is found that these two material models show qualitatively similar results. Furthermore, the comparison with the experimental results reveals, that the Neo-Hooke material model reproduces the effect of pre-stress on the difference in the Lamb wave phase velocity very well in most cases. For the $A_0$ wave mode at higher frequencies, however, the sign of this difference is only correctly predicted by the Murnaghan model. In contrast to this the Murnaghan material model fails to predict the sign change for the $S_0$ wave mode.