Damage detection of plate using the wavelet-based contourlet transform method

The purpose of this study is to present a new method of plate damage detection using the wavelet-based contourlet transform method. The contourlet transforms developed based on the Wavelet transform is a new two-dimensional transform that overcomes the limitations of the wavelet transform. The wavelet-based contourlet transform is a new family of contourlet transforms with the same two-step characteristic introduced from the same filter banks, radial, and angular decomposition. This method is used in plate damage detection for the first time. In the first step, the plate using the wavelet transform is decomposed into four sub-bands. Then, a radius decomposition with eight bands in each sub-band of the initial image is introduced using one of the directional filter banks. The radius decomposition in different directions is known as the advantage of this method in comparison with the wavelet transform. This advantage is observed in images with curved lines. In this method, the change in the elastic modulus is considered as damage in plates. The fundamental mode shape of intact and damaged plates is first obtained from the structural frequency analysis. Then, the location, shape, and approximate size of damage are obtained by applying this transform to the responses of the structure.