rainflow access

[thi]

hello!

i need a vbs script, that generates a rainflow matrix from a time-date channel (should be not so diffifcult) and then acess every entry in the rainlow matrix to do some further calculation (in specific: fatigue life evaluation)

who can help me?

[Brad_Turpin]

Hi thi,

There is a Rainflow Analysis function in the Professional package of DIAdem, in with the other "Statistics" routines (at the far right of the icon bar).  Have you found that yet?  I can send you a VBScript example if you want, but it has a rather large data set that it uses.

Brad Turpin
DIAdem Product Support Engineer
National Instruments

[thi]

hi brad,

thank you very much for your reply. I would be very happy to get the VBScript, since i cannot find the commands to access the values

In detail, i need to get the class limits and the counts of i.g. class number (1,4)..

May email-adress is decker@iabg.de

[Ingo_Schumacher]

Hello Thi,

are you aware of the Ctrl&A shortcut you can use in all the dialogs in DIAdem?
It will copy all variables that can be set within that dialog to the windows clipboard - or, if you are in teachin mode and just creating a new script, it will copy the variables to your script.

So, if you need to know the variables you need to read out to get the class width for example, just enter the rainflow dialog, go into the subdialog "classes" and press Ctrl&A. Cancel the dialogs, go to your script and press Ctrl&V and you will get something like:

CLASSMETH2       ="Automatic"
CLASSNO          =10
CLASSWIDTH       =180.018000030518
CLASSBEGIN       =6.3305316E+10
CLASSRANGEWIDTH  =1800.18000030518
CLASSEND         =6.330531780018E+10

Alternatively, just use the help button inside the dialog that contains the variables you are searching the name of.
This context sensitive help will tell you everything about the dialogs parameters and there variable names.

These variables are used during the calculation of the rainflow matrix and you can use them afterwards to access the vaues that have been used. As you can see, there is no array containing the limits of all the classes, but with the information given you can easily calculate this.

If you have to access the results that have been stored in channels, you can always use the ChD(line,channel) variable. And if you need to do this very often, prefer ChDX(line,channel) instead - its much faster.

Hope you find this information useful.
regards

[thi]

Hi Ingo,

STRG+A was the best hint i years.. say: decades! YOu helped me a lot!

c.u.

Thi

[Pat_Cas]

Hi Brad,

We running Diadem 10.0 but with the Advanced addition. I've tried using the Rainflow Classification funtion "ChnRainCalc" but wasn't sure how interpret it's result yet. Could you also send me that VB script on Rainflow that you sent to Thi. 

My email address is pfay@cascadeaerospace.com

Thanks.

Pat

[Brad_Turpin]

Hi Pat_Cas,

I posted the example VBScript application (6.2 MB) I mentioned on NI's outgoing ftp site.  The Rainflow Analysis function is part of the DIAdem Professional version, but you have the ability to call any function programmatically with your DIAdem Advanced, so the example ought to run fine for you.  The application is pretty simple, but the example data set is quite large.

Brad Turpin
DIAdem Product Support Engineer
National Instruments

[thi]

Hi Brad,

another qoestion concerning the rainflow-conting algorithm (in special. range-pair output):

I calculated range-pair counts using

    CLASSNO          =20
    CLASSBEGIN       =0
    CLASSEND         =20
    CLASSWIDTH       =0.5
    CLASSRANGEWIDTH  =20
    Call CHNCLASSRGPAIR(AktInput_,AktOutputAmp_,AktOutputCyc_,"NoBeginWidth","absolute",0,"Cumulative")

and got some implausible results (maximum range less then half of the expected value, implausible cycle distribution).

When I am using ChnRainCalc(..) with 

RAINONEPARACALC(3) = 1    'for rangepair and 
RAINONEPARACALC(4) = 1    'for levelcrossing output

the results seem to be OK.

Is there an explanation somewhere, wich algorith is used by CHNCLASSRGPAIR(..) and ChnRainCalc(..) respectively? I can't find anything in the online handbook. An explanation of the way, the residuum is handled would be helpfull, too.

Thanks,

Thi

[thi]

Hi Brad,

problem ist solved. Using CHNCLASSRGPAIR i asumed that (like with other programs), CLASSBEGIN and CLASSEND are the begin and the end of the range-classes (with rangpair, this would be 0 and max-min of the signal analysed).

With CHNCLASSRGPAIR, CLASSBEGIN and CLASSEND are min / max-value of the analysed range.

Since this is a dangerous source of misinterpretation, it shoul be stated clerly in the onlne-help!

Bye

Thi

[xzhcong]

Hello,

    I need the example for Rainflow calculation,but I could not down the example.Could some body sent it to me?

My email is :364289565@qq.com

Thank you and best regards,