Damage identification method based on continuous wavelet transform and mode shapes for composite laminates with cutouts

2018 ◽  
Vol 191 ◽  
pp. 12-23 ◽  
Author(s):  
Jie Zhou ◽  
Zheng Li ◽  
Jianlin Chen
2013 ◽  
Vol 330 ◽  
pp. 225-230 ◽  
Author(s):  
Xin Gang Li ◽  
Qiang Chen ◽  
Shu Hua Chen ◽  
Yue Min Wang ◽  
Guo Zhi Song

According to the characteristics of wave propagation in steel plate, choosing the suitable excite mode and frequency. Based on the wave structure of A0S0, obtaining its displacement discipline, then arriving at the sensitivity effect for different depth of defect in different frequency. Making different depth circular damage in the steel plate, calculating the law of lamb wave in different damage by using continuous wavelet transform.


Author(s):  
Mohammad-Reza Ashory ◽  
Ahmad Ghasemi-Ghalebahman ◽  
Mohammad-Javad Kokabi

Delamination is a common defect in composite plates that may cause significant losses in commercial applications. In this study, a hybrid damage detection method was introduced, which raised both the damage identification sensitivity level and detected quantitative damage parameters. The primary damage location was pinpointed by the wavelet transform, and the damage parameters, including location, depth, and intensity, were then isolated by the model updating process. The wavelet transform was obtained according to the signal’s nature, which leads to improvement in the wavelet transform’s operation. Then, the lifting scheme algorithm process was performed to increase the wavelet efficiency in damage detection. In addition, a proper signal, based on strain energy, was used for damage detection by the wavelet transform. Finally, the genetic algorithm method was employed in the proposed model updating method to identify the damage parameters through employing a novel error function. The selected error function was based on strain energy, having the best operation among previously identified modal criteria. Consequently, the accuracy of identifying the damage parameters was improved upon utilizing the proposed method, particularly in the presence of noise. In addition, the solution performed faster than the previously available updating methods which utilized only the genetic algorithm-based on mode shapes and natural frequencies for detecting the damage.


2020 ◽  
Vol 14 (54) ◽  
pp. 36-55
Author(s):  
Mallikarjuna Reddy ◽  
Arun Kumar K

 In the process of structural damage detection using continuous wavelet transform (CWT), the perturbation or damage is located by identifying the defects locally in the input signal data.  In this work the damage identification procedure using continuous wavelet transform is developed. This method is studied numerically using a simple beam model. The influence of reduced spatial sampling using fundamental mode shape is investigated in detail. The method is also investigated to ascertain the smallest level of damage identified using strain energy mode shape data.


2017 ◽  
Vol 31 (5) ◽  
pp. 668-688
Author(s):  
Ahmad Ghasemi-Ghalebahman ◽  
Mohammad-Reza Ashory ◽  
Mohammad-Javad Kokabi

Damage detection using the wavelet transform was investigated and appropriate approaches to raising the method’s sensitivity level were proposed. In addition, the current study attempted to implement the impulse wavelet design algorithm in order to present appropriate wavelet function with respect to the characteristics of the signal. The initial wavelet function corresponding to the impulse response of composite plate was achieved using impulse wavelet algorithm in time domain. The function was optimized using lifting scheme method. To detect damages, an appropriate signal was selected through applying wavelet transform. To enhance damage identification, first, the edges’ effect of wavelet transform was removed, then a higher accuracy was observed by summing the wavelet coefficients in all scale factors for each mode shape and the wavelet coefficients for all mode shapes. The article also presents a quantitative measure to compare different wavelets.


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