Numerical investigation of dispersive behaviors for helical thread waveguides using the semi-analytical isogeometric analysis method

In this paper, we propose a semi-analytical isogeometric analysis(S-IGA) approach in the twist space to investigate the dispersive properties in helical thread waveguides, which combines the advantages of the spectral approach and IGA. The convergence and accuracy of the proposed method are discussed, by comparing S-IGA results with reference solutions. Additionally, the analytical expression of axial offset wavenumbers is derived to explain the difference of spectrograms between the Cartesian and twisted systems. In order to illustrate the effectiveness of the proposed method, some dispersion curves of elastic wave propagation in helical thread waveguides are presented for a wide range of thicknesses and tortuosities.