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From Rainflow Matrix to Range Pair Count, need some clearification

Hi everybody,

I am new to rainflow analysis as well to DIADEM and trying to understand how cumulative data are obtained from a rainflow matrix.

As an example consider the following  5x5 rainflow matrix:

 

0   2   0   1  0

1   0   2   0  1

1   2   0   1  1

0  1    2  0   1

0  0    0  0   0

 

The Rainflow matrix entries R[i,j] contains if I well understand the number of cycles with range amplitude from class i to class j.

so summing the elements of the first subdiagonals (left and right of the main diagonal) we get the number of cycles with amplitude 1 class width.

Moving away from the main diagonal we get the number of cycles with higher amplitude. (Am I getting it right?)

 

For what I understood the range pair count is done by summation of the elements on sub-diagonals parallel to the main diagonals

From "NI Documentation" litterally "For example, DIAdem specifies the collective of range pair counting from the rainflow matrix by calculating the sum of the cycles along the diagonals parallel to the main diagonal."

Neverthenless performing a Rainflow analysis with DIADEM and checking to have also the "rainflow matrix" as result, it seems to me that the calculated range pair are so calculated:

Range[1] = Sum of element of the whole matrix;

Range[2] = Range[1] - [Sum of the elements of the diagonals next to the main]

Range[3] = Range[2] - [Sum of the elements of the next two subdiagonals]

 

....

For the matrix above I will get:

Range[1] = 16;

Range[2] = 16 - 11 = 5;      (First subdiagonals are [2 2 1 1] and [1 2 0)

Range[3] = 5 - 3 = 2;          (Second subdiagonal  are [0 0 1] and[ 1 1 0])

Range[4] = 2 - 2 = 0;          (Third subdiagonals  are [1 1] and [0 0])

Range[5] = 0;                     (Last subdiagonals are [0] and [0])

 

But for what I understood shouldn't I get just [0 11 3 2 0].

 

Where am I loosing something?

 

Sorry if my question is not clear enough please feel free to ask me for clearifications.

Thanks a lot for your Help

 

 

 

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