A spectral method for computing the effect of stress on guided modes in plates and rods

摘要

This paper presents a numerical approach based on spectral methods for the computation of guided ultrasonic wave modes in stressed elastic plates and rods. The approach is applicable to Lamb modes in anisotropic plates and longitudinal modes in isotropic rods under uniform stress. The proposed approach computes the modeshapes and the full complex dispersion spectrum (real frequency, complex wave-number), accommodating both propagating (real wavenumbcr) and non-propagating (complex wavenumbcr) modes. Numerical results are presented for plates composed of fiber-reinforced graphite/epoxy (GREP) and plates and rods composed of Hecla 17 steel. The results are used to investigate and compare the effect of stress on the dispersion curves for plates and rods, while demonstrating the computational efficiency of spectral methods. The convergence rate is demonstrated, showing spectral convergence.