Need to check my Rainflow analysis subroutine

[Sameradeeb]

Hi all,
I created a subroute for Rainflow analysis (Simplified rainflow counting for repeating histories) and I need to check whether my routine gives the right answer or not. I checked with "flaw check demo version" which can only run one demo file and I am predicting an extra cycle in the high range and missing a cycle in the low range. Anyway, is there any free software or any one can help me check my routine out. I made in VBA
Thanks in advance
Samer

 

[KalleH]

Samer,

I have constructed the following subroutine, which I have checked using handbook methods and LMS tekware. (I will however not guarantee its accuracy.)

Public Sub FromToRainFlow()

'Counts cycles according to the rain flow algorithm.
'Precondition: dPeaks[]
'Postcondition: dFromToRain[]

Dim i, j, p As Long
Dim dWorkPeaks(1, 50000) As Double
Dim lWorkPos As Long
Dim lPeakPos As Long

Dim dFirstPeak As Double
Dim dMidPeak As Double
Dim dLastPeak As Double

Dim dFrontFlank As Double
Dim dBackFlank As Double

Dim sOutString As String

'initializes the lNoCycles[] array
For i = 1 To iNoCh
lNoCycles(i) = 0
Next i

'dWorkPeaks(b,i,n) b=0 -> subarray containing the level of the peak
' b=1 -> subarray containing the index of the peak in dPeaks[]
' i -> channel number
' n -> index

For i = 1 To iNoCh
dNoiseLvl = dMaxMax(i) / 1000

'Enter info for the first 3 peaks
dWorkPeaks(0, 0) = dPeaks(i, 0, 1)
dWorkPeaks(0, 1) = dPeaks(i, 0, 2)
dWorkPeaks(0, 2) = dPeaks(i, 0, 3)
dWorkPeaks(1, 0) = 1
dWorkPeaks(1, 1) = 2
dWorkPeaks(1, 2) = 3
lWorkPos = 2
lPeakPos = 2
Do While lPeakPos < lNoPeaks(i)
p = p + 1
'refills dWorkPeaks if it contains less than 3 peaks
If lWorkPos < 2 Then
For j = 1 To (2 - lWorkPos)
lPeakPos = lPeakPos + 1
lWorkPos = lWorkPos + 1
dWorkPeaks(0, lWorkPos) = dPeaks(i, 0, lPeakPos)
dWorkPeaks(1, lWorkPos) = lPeakPos
Next j
End If

dFirstPeak = dWorkPeaks(0, lWorkPos - 2)
dMidPeak = dWorkPeaks(0, lWorkPos - 1)
dLastPeak = dWorkPeaks(0, lWorkPos)
dFrontFlank = Abs(dLastPeak - dMiddlePeak)
dBackFlank = Abs(dMiddlePeak - dFirstPeak)

' dFromToRain[] contains the individual rain flow cycles
' dFromToRain(i,b,m) i -> channel

' b=0 -> start of cycle, index of peak in dPeaks[]
' b=1 -> mid of cycle, index of peak in dPeaks[]
' b=2 -> end of cycle, index of peak in dPeaks[]
' b=3 -> start of cycle, level
' b=4 -> mid of cycle, level

' m cycle index

If dFrontFlank > dBackFlank - dNoiseLvl Or dFrontFlank = dBackFlank Then
lNoCycles(i) = lNoCycles(i) + 1
dFromToRain(i, 0, lNoCycles(i)) = dWorkPeaks(1, lWorkPos - 2)
dFromToRain(i, 1, lNoCycles(i)) = dWorkPeaks(1, lWorkPos - 1)
dFromToRain(i, 2, lNoCycles(i)) = dWorkPeaks(1, lWorkPos - 0)
dFromToRain(i, 3, lNoCycles(i)) = dWorkPeaks(0, lWorkPos - 2)
dFromToRain(i, 4, lNoCycles(i)) = dWorkPeaks(0, lWorkPos - 1)
dWorkPeaks(0, lWorkPos - 2) = dWorkPeaks(0, lWorkPos)
dWorkPeaks(1, lWorkPos - 2) = dWorkPeaks(1, lWorkPos)
lWorkPos = lWorkPos - 2
Else
lWorkPos = lWorkPos + 1
lPeakPos = lPeakPos + 1
dWorkPeaks(0, lWorkPos) = dPeaks(i, 0, lPeakPos)
dWorkPeaks(1, lWorkPos) = lPeakPos
End If
Loop
Next i

End Sub

 

[Sameradeeb]

Kalleh,
Thank you so much for your reply. I will check it with mine.
Samer