A Dynamic Stiffness Element for Free Vibration Analysis of Delaminated Layered Beams

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 DSM		Wang et al., as reported in [8, Table  1]		Della and Shu [8]		FEM [6]
	Mode 1	Mode 2	Mode 1	Mode 2	Mode 1	Mode 2	Mode 1	Mode 2
Intact	22.39	61.67	22.39	61.67	22.37	61.67	22.36	61.61
0.1	22.37	60.80	22.37	60.76	22.37	60.76	22.36	60.74
0.2	22.36	55.99	22.35	55.97	22.36	55.97	22.35	55.95
0.3	22.24	49.00	22.23	49.00	22.24	49.00	22.23	48.97
0.4	21.83	43.89	21.83	43.87	21.83	43.87	21.82	43.86
0.5	20.89	41.52	20.88	41.45	20.89	41.45	20.88	41.50
0.6	19.30	41.03	19.29	40.93	19.30	40.93	19.28	41.01