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Measuring a variable hole area in rotating assembly

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Measuring a variable hole area in rotating assembly

Hello, 

I have a valve plate of an axial piston pump and a plate of piston block. The valve plate performs one revolution.
I need to measure time-dependent area over which oil can flow (for one piston bore).

 

Is there any option to measure this in creo ? 

 

Thank You 

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Re: Measuring a variable hole area in rotating assembly

It sounds like you have a license that allows you to do mechanism analysis, so:

 

Attach to your mechanism 2 "phantom" parts that describe the fluid volume domains (essentially the "negatives" of the openings in your two circular plates).  Make them 1 unit thick and position them such that they interfere completely when you have full flow.  Since these volumes are 1 unit thick and they are moving on a plane, the numerical value of their volumetric overlap will equal the area of the opening(s).

 

So to add the volume interference analysis feature, it's a bit of a journey, as the function is buried a ways down.  First, find in Analysis tab, the tool "Pairs clearance" (under the "Global Interference" fly-out menu in the "Inspect Geometry" group).

Start it, put your two phantom parts into the "from" and "to" object collectors, and be sure to save the analysis as a feature (change quick->feature; I also called it "INTERF").

Before saying "OK" and quitting the the Pairs clearance tool dialog box, switch to the Feature tab and check "INTERFERENCE_VOLUME" as the parameter of interest (I also changed the name to "VOL").

 

That's pretty much it for the setup in the assembly mode.  You would then switch to the Mechanism application, set up a motion analysis and then after you get its result set, you can go into the "Measures" tool in the "Mechanism" tab in the Analysis group.  You should be able to select the parameter "INTERF_VOL" and the results set, and then the button to graph it should light up and you can generate it:

mechanism_measure_analysis.png

 

View solution in original post

8 REPLIES 8
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Re: Measuring a variable hole area in rotating assembly

An automatic push a button way? Not that I know of. Any method is going to take a bit of work. If I wanted to do this in Creo, I'd probably do something like the following:

 

(1) Make an assembly of the two plates, with an angular constraint between them. You probably want to use a couple of planes to define the angle, to avoid the weird behavior of Creo with respect to angular constraints.

(2) Within that assembly, create a third part, defined with the following features:

      a. A protrusion copy of "part 1" to a depth.

      b. A protrusion copy of "part 2" to the same depth. The result will have all the open area at this angle setting.

      c. A protrusion to a lesser depth so there are pockets for each open area.

(3) Now you can create an analysis feature of the area of the pockets (When you do Measure->Area and pick the pocket bottom, it will select all the areas).

(4) Record the results for each increment of the angle between the two discs.

 

Probably a bit tedious, but it'll get the job done. You'd have to decide how granular your data need to be based upon what you see for results.

If I wanted to be able to iterate on the dimensions of the two discs, I'd probably write a program or (maybe?) use Excel to calculate the effects. Iterating with Creo could be really time-consuming.

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Re: Measuring a variable hole area in rotating assembly

It is not nasassary to do it in Creo, I just thought it is possible to do it in some User-defined Mechanism Measures, but I dont know how. 
It can work by your way but I need about 7200 values in one revolution,
So its not exactly what I need 

But thank you for your time 

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Re: Measuring a variable hole area in rotating assembly

It is possible with Creo. You can drive the rotation with a servo in mechanism mode and create analysis features to measure at each time step items of interest. In order to plot the analysis vs time or export the data set will require the BMX module.

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Re: Measuring a variable hole area in rotating assembly

I have already done what you described, but I see no option for measuring the area I want

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Re: Measuring a variable hole area in rotating assembly

You will need to create the analysis features. You will need to create some geometry that defines the measurements as a function of position (use surfaces/quilts) and then measure from this at each time step. As I mentioned this is not going to be automated for the time steps within Creo unless you have the Behavioral Modeling Extension.

 

See below about analysis.

 

Analysis features 

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Re: Measuring a variable hole area in rotating assembly

Yeah, that's a huge amount of points. Sounds like a programming job, for sure. It'd be kind of fun.

Highlighted

Re: Measuring a variable hole area in rotating assembly

It sounds like you have a license that allows you to do mechanism analysis, so:

 

Attach to your mechanism 2 "phantom" parts that describe the fluid volume domains (essentially the "negatives" of the openings in your two circular plates).  Make them 1 unit thick and position them such that they interfere completely when you have full flow.  Since these volumes are 1 unit thick and they are moving on a plane, the numerical value of their volumetric overlap will equal the area of the opening(s).

 

So to add the volume interference analysis feature, it's a bit of a journey, as the function is buried a ways down.  First, find in Analysis tab, the tool "Pairs clearance" (under the "Global Interference" fly-out menu in the "Inspect Geometry" group).

Start it, put your two phantom parts into the "from" and "to" object collectors, and be sure to save the analysis as a feature (change quick->feature; I also called it "INTERF").

Before saying "OK" and quitting the the Pairs clearance tool dialog box, switch to the Feature tab and check "INTERFERENCE_VOLUME" as the parameter of interest (I also changed the name to "VOL").

 

That's pretty much it for the setup in the assembly mode.  You would then switch to the Mechanism application, set up a motion analysis and then after you get its result set, you can go into the "Measures" tool in the "Mechanism" tab in the Analysis group.  You should be able to select the parameter "INTERF_VOL" and the results set, and then the button to graph it should light up and you can generate it:

mechanism_measure_analysis.png

 

View solution in original post

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Re: Measuring a variable hole area in rotating assembly

Wow, You are the best
This is exactly what I needed
Thank you very much !!!

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