Table 1: Natural frequencies of the delaminated beam, with a split occurring symmetrically about the midsection along the midplane [1]; DSM, CM, FD-FEM, and standard FEM models.

Delamination Length Present DSMWang et al., as reported in [8, Table  1]Della and Shu [8]FEM [6]
Mode 1Mode 2Mode 1Mode 2Mode 1Mode 2Mode 1Mode 2

Intact22.3961.6722.3961.6722.3761.6722.3661.61
0.122.3760.8022.3760.7622.3760.7622.3660.74
0.222.3655.9922.3555.9722.3655.9722.3555.95
0.322.2449.0022.2349.0022.2449.0022.2348.97
0.421.8343.8921.8343.8721.8343.8721.8243.86
0.520.8941.5220.8841.4520.8941.4520.8841.50
0.619.3041.0319.2940.9319.3040.9319.2841.01