Damage identification method of simply supported beam under ambient excitation based on wavelet packet energy curvature
In order to identify the damage time and location of simply supported beams under ambi-ent excitation,a damage identification method for simply supported beams based on wavelet packet energy is proposed.Firstly,wavelet packet technology is used to process the displacement response time history data of a simply supported beam with healthy state and unknown state under ambient excitation,and its wavelet packet energy is obtained.Then,based on the energy proportion of each sub band,the optimal frequency band is selected and normalized to obtain the energy curvature.Finally,using the damage identification index calculated by the energy curvature of the wavelet packet in a healthy state as a reference,the damage identification index of a simply supported beam in an unknown state is compared to obtain the single or multiple point damage status in the struc-ture,including the time,location,and relative degree of the damage.The numerical simulation re-sults of a simply supported beam show that when the signal to noise ratio is no less than 40 dB,this method can accurately identify the damage status of the structure.
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