In their paper [1], Kim and Wang presented the vibration analysis of composite beams by using a finite element-based formal asymptotic expansion method. After a detailed mathematical treatment of the formal asymptotic method-based beam analysis (FAMBA), they considered various examples of composite beams with solid and closed thin-walled cross sections for verification purposes and the numerical results were compared with those from 3D FEM and other methods, such as the variational-asymptotic beam section analysis (VABS) [2].
One particular case, the 15 deg CUS thin-walled composite box beam (whose ply material properties are listed in Table 3 of [1]), was analyzed with VABS by taking the stiffness model given in [2] and applying it to a typical Rankine–Timoshenko beam model. The normalized first and second eigenvalues computed by 3D FEM, FAMBA, VABS, etc. were plotted against the beam length-to-height ratio in Figs. 6...
