Numerical calculation of guided wave disperse curve in helix wire based on semi-analytical finite element method

Disperse curve computation of guided wave in helix wire is complex but important for analysis of elastic wave propagation in steel strand and wire rope. Detailed analysis of physical model can hardly get analytic solution, while some usual simplification of model will lead to the loss of physical meaning. First a helical coordinate system is proposed in this paper. A semi-analytical finite element method is applied to elastodynamics equation for the calculation of wavenumbers. The displacement, strain and stress vectors are obtained by tensor analysis. And the relationship among them is deduced. The result shows the disperse behavior of guided wave in helix wire, which is depended on lay angle. That is different from straight wire, which is owed to its particular helix geometry structure.