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how to extract x,y and z direction components of force

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Old   December 19, 2012, 08:45
Default how to extract x,y and z direction components of force
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dke
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Hi all,

Im currently working on a student research project and i'm computing wave loads on an offshore structure.
The simulation is working fine, but i'm stuck at extracting force components.

My intention is to extract the force components. Force in X, Y, and Z direction at specific coordinates.
For example at the point [1,2,3] i want to extract a force in form of [200N,300N,500N].

I already tried Force report, but this gives me only the accumulated force for the whole structure.

My second try was to use a XYZInternalTable, but i only receive the pressure at specific coordinates given by star ccm+ without knowing the reference surface to calculate the force from pressure.

Currently i'm stuck at trying user defined field functions.

Maybe any suggestions?
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Old   December 19, 2012, 12:02
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dke
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Well, i found a part solution:

Now i'm able to extract components for Forces caused by wall shear stress.

For example:
Force components [i j k]: [0.0 0.0 0.025]
corresponding Position: [x y z] [-29.73 -18.75 -64.5]


Im using a XYZInternalTable with the following user defined function as scalar field function:

Code:
$$Area * $$WallShearStress.mag()
Now the next problem occured. I cant use the same code syntax for pressure related forces, because pressure function is of scalar type.
My first idea was that i could use the scalar pressure value just as the magnitude of a potential pressure vector. Star reacts with an an error : "Pressure is not a type of array".
Now i'm confused how to continue to get the values i'm looking for

Last edited by dke; December 19, 2012 at 13:35. Reason: Code corrected
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Old   December 19, 2012, 12:43
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dke
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Yay simple syntax mistake.

$Pressure instead of $$Pressure works

So field function for Pressure induced Force:

Code:
$$Area * $Pressure

Last edited by dke; December 19, 2012 at 13:35. Reason: Code corrected
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Old   December 19, 2012, 15:30
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Ryne Whitehill
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Don't bother making field functions, a force report is the right way to do this.

In the force report, there is a "direction" component. You can set up 3 reports, one for X, one for Y, one for Z.


edit: I misunderstood your problem, my apologies! Ignore the above

Last edited by rwryne; December 19, 2012 at 16:02.
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Old   December 19, 2012, 15:51
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Joern Beilke
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The report doesn't help you for displaying the distribution of the force on a surface within a scalar plot. It just gives you a final number.

For a scalar plot of the y-component you have to create a scalar field function like this:

Code:
$Pressure * $$Area_Normal[1]
where $Area_Normal is a vector FV:

Code:
$$Area/$$Area.mag()
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