Abstract Based on linear three-dimensional elasticity, the equations of wave motion for coupled Lamb waves are derived by using a Legendre orthogonal polynomial approach when waves propagate along non-principal directions of the material, and the coupled equations of wave motion are also solved numerically. Firstly, for verifying the applicability and validity of this proposed method, this approach is applied to isotropic material and obtained results are compared to known results. Then, the phase dispersion curves of coupled Lamb waves along different non-principal directions are calculated, and the effects of the different propagation directions on fundamental modes and high-order modes are investigated. Finally, the distributions of phase and group velocities of fundamental modes are shown respectively, which have the great potential for structural health monitoring of anisotropic materials.Simultaneously, the reason that S0 mode is the most sensitive to the change of the propagation direction is illustrated with considering of both displacement distribution of fundamental modes and material’s anisotropy property.
2013, Vol. 34 
