2D wavelet transform of modeshape values of plate structures

I have a 2-dimensional mode shape of plate structures and I put the data of mode shape in a matrix which the first column in the matrix is x coordination of plate and the second column of the matrix is the coordination of y and the third column is the mode shape point of each nodal point.

In the case of damage detection can I calculate 2-dimensional wavelet transform for f(x,y)

I would appreciate if you help me with Calculation in MATLAB for 2d continuous wavelet transform.

Answer 1

[Prasanna]

Hi Abina,

It is my understanding that you have a matrix containing x and y coordinates of a plate structure, along with mode shape values for each nodal point, and you're interested in performing a 2D continuous wavelet transform (CWT).

To calculate the 2D CWT for your mode shape data, you can refer the following steps:

• Prepare your data: Ensure that the data is organized in a matrix where each row corresponds to a nodal point with columns for the x-coordinate, y-coordinate, and mode shape value.
• Set Up the Wavelet Transform: Choose an appropriate wavelet for your analysis. You can use the default ‘morlet’ wavelet or choose a corresponding wavelet from https://www.mathworks.com/help/releases/R2021a/wavelet/ref/cwtftinfo2.html
• Perform the 2D CWT: The ‘cwtft2’ function can be used to compute the 2D CWT. This function takes in the input numeric data, and has other optional pairs of arguments like angles, norms and scales which can be further set. The cwtft2 function uses a Fourier transform-based algorithm in which the 2-D Fourier transforms of the input data and analyzing wavelet are multiplied together and inverted.

For more information, you can refer the following documentations:

• cwtft2: https://www.mathworks.com/help/releases/R2021a/wavelet/ref/cwtft2.html
• cwtftinfo2: https://www.mathworks.com/help/releases/R2021a/wavelet/ref/cwtftinfo2.html