Analysis of Guided Waves Dispersion and Acoustoelastic Effect in Stressed Waveguides by Eigenfrequency Method and Experimental Study

Resumo

On the basis of the effect of initial stress and acoustoelastic coefficients on the dispersion behavior of guided waves in stressed waveguides. a finite element method is presented to analyze the wave propagation in prestressed waveguides. The approach was based on the acoustoelastic theory to solve the eigenfrequency of prestressed waveguides, where wavenumbers and modes are distinguished by modal shape, and the solutions of the phase velocity and the group velocity were determined. The algorithm was applied to analyze the dispersion and acoustoelastic coefficients of a prestressed plate and an axisymmetric bar model. Obtained results were consistent with previous research, proving that the approach is useful for the analysis of dispersion and acoustoelastic effect in prestressed waveguides. The acoustoelastic effect of the longitudinal mode guided wave in the rod was experimentally studied according to on the method of eigenfrequency analysis. The results show that the trend of the experimental results is in good agreement with that of the eigenfrequency method. The detection frequency of L(0.1) mode is around 72 kHz, the error of L(0.2) mode is small in the range of 240–280 kHz, which is more suitable for acoustoelastic stress detection.