A Damage Prognosis Method of Girder Structures Based on Wavelet Neural Networks

Table 1

Comparison of updated frequencies and measured frequencies, MAC values (unit, Hz).

Model number	Measured frequencies ①	Updated frequencies ②	Relative error; (②−①)/① (%)	MAC values (%)
beam-0
First order	33.62	32.78	−2.5	93.1
Second order	135.03	130.78	−3.1	91.4
Third order	293.03	293.02	0	95.5
beam-1
First order	20.71	22.02	6.3	95.1
Second order	131.02	130.04	−0.7	93.4
Third order	231.18	232.69	−0.7	90.9
beam-2
First order	18.90	19.46	2.9	96.7
Second order	85.94	90.67	5.5	94.3
Third order	202.54	203.07	0.3	90.8
beam-3
First order	17.02	17.29	1.6	94.7
Second order	66.69	67.14	0.7	94.9
Third order	148.33	149.68	0.9	90.2