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thomas100

how to request force-displacement curve(ls-dyna solver)

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Hi,


 


 


Recently I have done a crashing simulation, but I can get force-time curve from key word RCFORCE and the displacement information from key word NODEOUT. But I just cannot combine them into force-displacement curve.


 


Is there any way that I can do it?


 


Many thanks.


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Hi,

 

1. create a displacement / time curve
2. create a force / time curve
3. create a new empty curve ("Add" in define curve panel)
4. switch to "Math" type
5. select at the "Curves..." selection dialog your displacment / time curve for x
6. select at the "Curves..." selection dialog your force / time curve for y
7. change the x (e.g. p1w1c1.x) into y (p1w1c1.y) at the curve for x (displacement)
8. press Apply and switch off curve one and two...

 

Best regards,
Mario

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Hi Mario,


 


Thank you for your reply. I just have another question.


 


I have successfully generate the force-displacement curve by following your instructions. Is it possible to apply a SAE 10Hz filter to the force-displacement curve I just generated since I can see there is a lot of noise within the curve.


 


 


Many thanks.


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I just got another issue. when I tried to apply the SAE60 filter to the force-displacement and force-time curves, I got two same warning message: referenced page is not valid. I didn't change the file location and haven't made any modification to the files. I can't figure out the meaning of this message???


 


 


Many thanks.


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Hi,


 


you can apply a low-pass filter of course only in a time domain (be sure, that you are using seconds).


Filter your force / time curve and use the new one for the creation of the force / displacement. You have to do the filtering before the creation of the new curve!!!


 


Install the MVP_Toolbar, a freeware tool from Altair. You can download it at ftp://ftp.altair.de/pub/hyperworks/support/macro_toolbars/ .


Here you have a very good menu and dialogs to adjust the filter class and so on. 


 


Your last issue i can't understand, check the parameters of your curves e.g. p1w1c1 means page 1, window 1, curve 1


 


Best Regards,


Mario


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Hi Mario,


 


If I don't use the MVP tool for filter (actually it looks like bit hard for me to get started), how should I apply a 10Hz filter to the curve?


 


I saw there is one option called SAE General which I think is a self defined tool to apply any filter class. For the 10Hz class, what should I put in the three displayed fields: curve(time=second), filter class, time conv. ?


 


Many thanks.


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Hi,


 


Curve: your force/time curve (double click on "curve")


Filter class: 10 (for 10 Hz)


time scale to s: 1 (if you have seconds) (you can still have a curve in ms, scale it here to second, since filters always need seconds)


 


In any case, try to install MVP_Toolbar and the life is a lot easier...


 


Regards,


Mario

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Hi Mario,


 


After adding the line "{mvp_toolbar_dir = "<adapt path>/MVP_Toolbar";include(mvp_toolbar_dir + "/preferences_macro.mvw")}" at the end of the preference file, i got a error message "could not preprocess the file" as soon as I open the hypergraph. 


 


Also in the installation guide saying "Load via the menu "Set Preference File ..."", but there is no option "set preference file" in the menu.


 


Please help.


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Hi Thomas,

 

add the following lines at the end of your preferences.mvw (located in directory HW):

 

{mvp_toolbar_dir = "C:/Altairwin64/MVP_Toolbar"}
{include(mvp_toolbar_dir + "/preferences_macro.mvw")}

 

C:/Altairwin64/MVP_Toolbar has to replace by your local location.

 

You can include the file of course in one line: {include("C:/Altairwin64/MVP_Toolbar/preferences_macro.mvw")}

Be sure that the directory points to your location.

For me it works in this way.

 

You can load preference files in Hyperview at "Files->Load->Preference File". First step is to register the file (press register and search your file). Second step ist to load it.

 

Best regards,

Mario

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Hi Mario,


 


Thanks for your tips.

 

Now I can see *filter, *misc etc. menu as soon as I open the HV without registering. Is this normal?

 

I have a look at filter menu, it looks like there is no predefined 10Hz filter. What should I do to pick up the 10Hz filter?

 

 

Many thanks.

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Hi Thomas,


 


all the menus from MVP_Toolbar have a star, thats OK.


10 Hz isn't a standard filter, so you have to go the manual way...


 


Regards,


Mario

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Hi,

 

it is answered some posts before... use the SAE General filter:

 

Curve: your force/time curve (double click on "curve")
Filter class: 10 (for 10 Hz)
time scale to s: 1 (if you have seconds) (you can still have a curve in ms, scale it here to second, since filters always need seconds)

 

Regards,

Mario

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good day mario


 


in define curve for load body.. how can i define the load_body curve as a horizontal line (ordinate value equal to the gravitational acceleration)


 


what value need I put in ordinate.? and also what value need I put in abscissa.?


 


hope you can help.. thanks.


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