“…Finally, the displacement and stress mode shapes of the laminate can be portrayed along the plate thickness direction through equations ( 8) and (9). For some composite aeronautic laminates that have symmetry in terms of stacking sequence, the solution points ðω,k * ,θÞ in equation ( 19) can be further classified into symmetric and anti-symmetric modes by checking the symmetry condition 42 of the computed displacement and stress mode shapes at the midplane of the whole laminate, as presented in equation (20) ( ½u 3 ,σ 23 ,σ 13 midplane ¼ ½0; 0; 0 symmetric modes ½u 1 ,u 2 ,σ 33 midplane ¼ ½0; 0; 0 anti À symmetric modes (20) With the solved dispersion relation between ω and k * at a specified θ 0 , phase velocity c p is computed from equation (21). If the damping effect is slight, that is, k i ( k r , meanwhile if the structure is quasi-isotropic, group velocity c g can be computed through equation (22), which is an isotropic model.…”