Wood Beam Damage Identification Based on the Curvature Mode and Wavelet Transform

Table 3

Changes in intrinsic frequency before and after damage.

Working conditions	1st order frequency		2nd order frequency
	Frequencies (Hz)	Relative frequency change (%)	Frequencies (Hz)	Relative frequency change (%)
0	76.55	—	264.14	—
1	76.55	0.00	264.05	0.03
2	76.52	0.04	263.80	0.13
3	76.42	0.17	263.02	0.42
4	75.95	0.78	260.28	1.46
5	75.14	1.84	256.22	3.00
6	73.90	3.46	250.81	5.05
7	76.53	0.03	264.15	0.00
8	76.46	0.12	264.16	0.01
9	76.19	0.47	264.19	0.02
10	75.20	1.76	264.23	0.03
11	73.65	3.79	264.20	0.02
12	71.45	6.66	263.74	0.15
13	76.51	0.05	264.05	0.03
14	76.39	0.21	263.80	0.13
15	75.99	0.73	263.01	0.43
16	74.51	2.67	260.25	1.47
17	72.29	5.57	256.14	3.03
18	69.34	9.42	250.64	5.11