rainflow cycle counting

[bx338-disabled]

Hi, can anyone post an example of a rainflow cycle counting worksheet (in version 2001).

TIA

Derek Ferguson
Cummins Inc

[ValeryOchkov]

What is it "rainflow cycle counting"
Val
http://twt.mpei.ac.ru/ochkov/v_ochkov.htm

[bx338-disabled]

val,

http://en.wikipedia.org/wiki/Rainflow-counting_algorithm

[ValeryOchkov]

Wiki is not an origin... for this forum.
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Val
http://twt.mpei.ac.ru/ochkov/v_ochkov.htm

[ptc-1265149]

Here is a copy of my Rainflow Cycle count demo file in MC2001 format.

[ptc-1368288]

On 3/27/2007 6:53:29 PM, rsoloski wrote:
>Here is a copy of my Rainflow
>Cycle count demo file in
>MC2001 format.
______________________

Mathcad 11 can't read ?
Must be 13 or 14 ??? not 2001 as you say !

jmG

[bx338-disabled]

My version of 2001 also can't read it. Can you put it in an earlier format please?

many thanks

Derek ferguson

[ptc-1265149]

Here is another try; I downsaved from MC12 to MC2001.

[ptc-1368288]

On 3/28/2007 9:53:55 AM, rsoloski wrote:
>Here is another try; I
>downsaved from MC12 to MC2001.
______________________________

Ah ! the smoking gun in there.

jmG

[ptc-1368288]

I understand mechanical fatigue as a Process Control Engineer (we care !). But fatigue of a data set is a bit esoteric for my small brain ? Especially a sinusoidal data set ... must look at it again . Spring fatigue of a car suspension, that is real as a 100000 km car suspension in the rocky desert is more damaged than same km on nice highway.

I must be missing some point in that proposal ?

jmG

[ptc-1265149]

The purpose of the sinusoidal dataset was only to show by example the usage of the cycle count routines.

[ptc-1368288]

On 3/28/2007 5:08:55 PM, rsoloski wrote:
>The purpose of the sinusoidal
>dataset was only to show by
>example the usage of the cycle
>count routines.
__________________

OK, then adapt to real data

jmG

[ptc-1368288]

On 3/28/2007 6:26:37 PM, jmG wrote:
>On 3/28/2007 5:08:55 PM, rsoloski wrote:
>>The purpose of the sinusoidal
>>dataset was only to show by
>>example the usage of the cycle
>>count routines.
>__________________
>
>OK, then adapt to real data
>
>jmG
___________________

... read more, read the attached.

Unless the "Rainflow cycle" applies to real life, you have not proved your proposal is usable as demonstrated in the first part of the work sheet. Raw data from capture should always (most of the time) be smoothed . Then below Marlett you can apply the Mathcad "local Min/Max". It locates all "peak/Valley", not missing any . In fact if "Rainflow cycle fatigue" purports to count all reversal of the 1rst derivative, then the part of the project below Marlett is done correct using the "local Min/Max".

The last part of the project is not done, i.e: pack all "Peak/Valley" and center them at the mean of the data set ...

Interesting project, thanks for the idea.
This project will surely be welcome in the future.

More collabs want to contribute ?

jmG

[ianward]

Rainflow sheet attached.
Written in Mcad 13 and saved as a 2001i file.
Hope you can read it OK....