PSI - Issue 52

Yuhang Pan et al. / Procedia Structural Integrity 52 (2024) 699–708 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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As mentioned in the last section, For the vibrational method, the features used are the nine principal components of the FRF in the range 500-2000 Hz after PCA dimensionality reduction. The values of these principal components obtained from pristine and damage state are showed in Fig.8(a), which demonstrates that features used in this research can capture the state change of the plate. Then the extracted features are input into the neural pattern recognition, and the number of training and testing datasets are same as the guided wave method. Results of the testing are summarized in Fig.8(b), which shows that the method is capable of identifying all of the damaged and pristine samples.

Fig. 8. Damage detection results obtained by vibration-based method: (a) Features used in the vibration method. (b) detection results obtained by the neural pattern.

For damage detection, the above results indicate that the damage plates are clearly separated from the pristine samples by the proposed vibration based and guided wave-based method. After detecting the damage, the next step based on SHM is to localize the damage, which is addressed in the next section. 4.2. Damage localization To verify the effectiveness of the proposed hybrid method in this research, features extracted from guided wave, the nine principal components extracted from vibration signal and their combination are selected as the input of BPNN model, respectively, and the damage location is selected as the output. As mentioned in the Section 4.1, a total of 144 sets of damage samples are acquired from different locations, and based on these data, 128 sets of data are used as training samples, while 16 sets of data are used for model validation. The predicted locations and true position by vibration signal and guided wave are shown in Fig.9.

Fig. 9. Damage localization results obtained by: (a) vibration-based method, (b) guided wave-based method-DI2.

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