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KRZ Datei erzeugen

Verfasst: Do 22. Sep 2011, 09:04
von rohr2support
Bei der Berechnung von dynamischem Druckstoß müssen die Kraft-Zeitverläufe in einer Datei ".krz" vorliegen.
Das Format ist entweder binär oder ASCII.
Falls man die Kräfte mit einer Tabellenkalkulation ausgerechnet hat, sind sie auch leicht als Textdatei abzuspeichern,
allerdings erfordert ROHR2 ein spaltengerechtes Format, dass sich mit den gängigen Programmen nicht ganz so
leicht erstellen läßt.
Daher stelle ich hier ein kleines Tool ein, um das ".csv" (Comma separated values) Format das man aus Excel oder Openoffice
heraus erzeugen kann in eine ".krz" Datei umwandeln kann.


Die Benutzung erfolgt auf der Kommandozeile:

Code: Alles auswählen

csv2kraz  input.csv
Das Format der *.csv Datei muss wie folgt aussehen.
Aufbau_krz.png

Viele Spaß damit?

Viel Lärm um nichts!

Verfasst: Do 22. Sep 2011, 09:13
von rohr2support
Zum Thema KRZ_Datei:
Hier kommt noch eine KRZ Datei mit 10 Sekunden gaußschem weißem Rauschen (Auflösung 1ms).
Diese kann man ganz gut als breitbandiges Testsignal für dynamische Untersuchungen verwenden.

MfG

Re: Create KRZ file

Verfasst: Fr 9. Aug 2013, 06:34
von rohr2support
For the calculation of dynamic time history events you need to provide the load inputs in form of load functions over time.
These are provided in a file called "*.krz" which is either binary or ASCII.
If the loads were calculated using a spreadsheet, it is easy to save them in Text format, but ROHR2 requires a column aligned format which
may be difficult to generate with popular programs.
Therefore we provide a small tool here which allows to convert a ".csv" (Comma separated values) format generated from Excel or Openoffice
into a "*,krz" file.

The usage is on the command line:

Code: Alles auswählen

csv2kraz  input.csv
The format of the *.csv file must be as follows:
format_krz.png
Have fun?

Create KRZ File from Excel/Libreoffice

Verfasst: Fr 1. Dez 2017, 13:52
von rohr2support
Dear Dynamic Freaks

The above post and the utility "csv2krz" is no longer necessary. Since Version 32.0 it is possible to open CSV Files directly with the ROHR2 input dialogue.
First you create a csv file from your data. You need to have the time steps in lines and the forces in colums.
E.g. in excel or Libreoffice you save a file that looks like this:
Impuls_Libreoffice.PNG
You save it to csv so it looks like this:
Time;F100;F50;F25;F10;F5;F2_5;F1;F05;F02;F01
0.0001;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0002;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0003;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0004;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0005;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0006;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0007;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0008;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0009;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000;0.0000
0.0010;2.5600;5.1200;10.2400;25.6000;51.2000;102.4000;256.0000;512.0000;1280.0000;2560.0000
0.0011;2.5600;5.1200;10.2400;25.6000;51.2000;102.4000;256.0000;512.0000;1280.0000;0.0000
0.0012;2.5600;5.1200;10.2400;25.6000;51.2000;102.4000;256.0000;512.0000;0.0000;0.0000
When you have created your transient load case in ROHR2 in the LC dialogue you click on the Browse button to select your Load Function file:
Select_KRZ.PNG
You will then see a window that allows to select which colums and row are usefull in your file:
Assign_colums1.PNG
So first you selct the title row which contains the load names.
1.) Click on the button "Click on row with load names" then
2.) click on line1 -> This line will be highlighted in red and the 1 appears next to the button:
Assign_colums2.PNG
Next you proceed in the same way for the first colum of the loads:
1.) Click on the button "Click column with first load name" then
2.) click on colum 1 -> This column will be highlighted in green and the 1 appears next to the button:
Assign_colums3.PNG
Then you specify the beginning of the time steps:
1.) Click on the button "Click on row with first timestep" then
2.) click on line2 -> This line will be highlighted in blue and the 2 appears next to the button:
Assign_colums4.PNG
Finally you select "Create File" and the KRZ file will be created and used in this load case.
Now you can assign the dynamic loads to your system using the load names from the first row.

Best regards

ROHR2 Support

Re: KRZ Datei erzeugen

Verfasst: Fr 2. Feb 2018, 17:07
von claudio_mend
Good afternoon,

I have been studying the input of waterhammer forces on my rohr2 models and found it a bit confusing. Is there any tutorial or example that the company provide to help us understand how its done?
If not, here are the doubts I'm dealing with:
2-How to identify on the input file for the hammer curves the nodes corresponding to each curve.
3-After running the problem, how to verify the resulting stress on each element over time and also the loads on equipment nozzles and restraints over time.
Thank you for the attention.
Claudio

Fluid Hammer Analysis

Verfasst: Mo 5. Feb 2018, 13:43
von rohr2support
Hi

The steps for a transient analysis are:
  1. Create a load case "fluid hammer dynamic"
  2. Select the file with the fluid hammer loads (see the post above)
  3. Assign the fluid hammer loads to the points
  4. run the calculation
  5. look at the results (video)
  6. evaluate stresses
The first two points are discussed above. Lets assumme your fluid dynamic load case is called "hammer".
Step 3:
In the transient load case "hammer" that you created goto "Loads-> Fluid hammer concentrated loads"
Then select the node where you want to add a transient load.
In the window "Fluid hammer concentrated load" there is a selection box "QXi" (means dynamic load in local coordinates: local X direction means axial to the pipe) you can find the list of load names that you inserted as title line in your force file over time.
Assign_fluid_hammer_loads.PNG
You may specify a factor which allows to scale the loads. (e.g. -1 or +1 to change the sign)
Step 4: Launch calculation
Step 5: When you select the load case "hammer" in the result view, ROHR2 will convert all the load steps into deformation images to create a "video".
Click on the play button to see the deformation video over time:
Time_hist_video.PNG
You can stop the video at any time or go back an forward with the direction buttons in the same way as on a video player.
At any time step you can have a look at all results, exactly the same way as you would do for a simple static load case.
Time_Step.PNG
You can also use the button "Show time-dependant results" in the Node result window to launch ROHR2FUN to display a single result over time.

Step 6:
If you have your stress analysis set on automatic equations, ROHR2 will automatically create a stress equation for occasional loads using the maximum bending moments of the whole time series (usually called hammer-MMi). You can check under LC->Stress Analysis->Equations.

Hope this helps as a first introduction.

Best regards

Rohr2 Support

Re: KRZ Datei erzeugen

Verfasst: Mo 5. Feb 2018, 19:18
von claudio_mend
Thank very much for the fast response.

I'm trying to follow the steps given by you, but I'm having the following error:
error1.PNG
This is the input file I'm using:
input.PNG
Do you have any Idea of what I'm doing wrong?

Thank you!

Re: KRZ Datei erzeugen

Verfasst: Di 6. Feb 2018, 12:18
von rohr2support
Hi

Maybe this is a problem with the decimal separator "," and the field separator in your csv file (they should be different)
Can you post the csv file content as text, not the excel screenshot to check?

Best regards

Rohr2 Support

Re: KRZ Datei erzeugen

Verfasst: Di 6. Feb 2018, 20:40
von claudio_mend
Hi,
thanks again for the fast response.
I was selecting the wrong column for the "column with first load name". Now I've got it right!
It works with comma, as I'm using ";" to separate columns as can be seen bellow:
timestep;F1;F2;F3
0;10;8;6
0,1;15;10;8
0,2;20;15;10
0,3;25;20;15
0,4;30;25;20

Thank you very much!