Structural Damage Detection Using Nonlinear Vibrations

Table 2

First 20 eigenfrequencies for the undamaged panel and for the three damages with their % variations.

Mode	(Hz)	D2, (Hz)	D2, %	D3, (Hz)	D3, %	D5, (Hz)	D5, %
1	7.95	7.79	−2.01	7.95	0.00	7.83	−1.51
2	11.38	11.37	−0.09	11.38	0.00	11.38	0.00
3	23.67	23.44	−0.97	23.67	0.00	23.51	−0.68
4	27.90	26.67	−4.41	27.90	0.00	27.60	−1.08
5	47.72	43.15	−9.58	47.72	0.00	46.56	−2.43
6	49.82	48.93	−1.79	49.82	0.00	49.11	−1.43
7	72.67	71.01	−2.28	72.58	−0.12	71.47	−1.65
8	83.43	73.63	−11.75	83.43	0.00	80.68	−3.30
9	87.70	85.73	−2.25	87.57	−0.15	86.44	−1.44
—	—	93.42	—	—	—	—	—
10	99.22	99.41	0.19	98.89	−0.33	98.20	−1.03
11	101.11	99.88	−1.22	101.10	−0.01	99.76	−1.34
12	101.22	109.68	8.36	100.97	−0.25	100.20	−1.01
13	114.46	114.63	0.15	114.45	−0.01	112.51	−1.70
14	117.42	117.48	0.05	115.53	−1.61	116.92	−0.43
15	118.05	117.86	−0.16	117.70	−0.30	117.86	−0.16
16	121.78	121.75	−0.02	121.77	−0.01	121.75	−0.02
17	121.82	126.57	3.90	121.65	−0.14	119.86	−1.61
18	128.90	131.10	1.71	128.88	−0.02	128.15	−0.58
19	137.98	137.16	−0.59	137.68	−0.22	137.36	−0.45
20	139.43	139.27	−0.11	139.34	−0.06	139.33	−0.07