NX9 - MEASURE BODIES / SOLID DENSITY

[Kenja824]

Quite often I have solid bodies that are not correct on the insides because it doesnt matter. I cannot add a material and get a correct weight, but I do know what the weight is supposed to be. The only way I know to get the weight correct is to keep playing with the Solid Density until I get the mass correct.

Is there a way to select a solid body and give it a specific mass and the solid density will adjust accordingly? I do need this body to be correct when doing a Measure Bodies. It cant just have a mass attribute given to it.

 

[Kenja824]

Sorry John. I just looked. I am not finding anything like that. It may be I am just blind again. That happens a lot these days. lol

If anyone finds that can you please take a snippit of the box and post it for me?

 

[Kenja824]

To add to Cowski's point about the equation for finding the Density needed. This works great but you have to be aware of what units you are using. I am not sure if out settings are common place or not, but we use the following....

Measure Bodies - Volume = mm3
Mass = KG
Density = Lbs/Inch

Why we use these I do not know. I found the formula to be... Density = ((mass*1000)/(volume/1000))*.0361273

Just in case someone uses the same settings as we do and needs to convert.

Thanks Cowski. Saves a lot of time knowing this.

 

[cowski]

Please note that the expression system can handle units for you. For your volume value, pick the "volume" dimensionality and units of mm^3. For your desired mass, pick "mass" and units of kg. Finally, for the density, pick "mass density" and units of lbm/in^3; for the formula enter the mass expression divided by the volume expression. The answer will be shown in the units that you chose.

www.nxjournaling.com

 

[Kenja824]

Ok I am confused a little. You say the system. You mean NX9? If so, I do not wish to change my settings for the units because they come up automatically like that and I know I would have to remember to reset them for other things. I figured it would be easier to just know the conversions and make myself an excel chart with that formula. So all I need to do is open the chart, add the two numbers and get my answer rather than change the units back and forth depending on what I am working on at the time.

Am I misunderstanding what you mean?

 

[cowski]

Am I misunderstanding what you mean?

Yes.
There is no need to change your current settings. When you create an expression, you can choose the dimensionality and units for that particular expression. When you assign units to an expression, NX can convert between unit systems for you or warn you if the units you are using are inconsistent with your entered formula (usually due to a user entry error in the formula).

www.nxjournaling.com

 

[Kenja824]

I was really confused about the talk of expressions until I went back and read your original post stating it sounds like a good time to put the expression system to use. Now I am only a little confused. lol I am guessing you mean to just create an expression to give these their density? (Will Measure bodies read these expressions?) Or to just figure out the density for me?

Sorry for not catching on to this faster. I have been wracking my brains trying to learn VBA code lately and feeling lost over it, and simpler things seem to fly past my grasp because of it lately.

 

[cowski]

(Will Measure bodies read these expressions?) Or to just figure out the density for me?

The expression system could calculate the density value that you need to assign; I don't know of a way to associatively tie an expression value to the density of a solid body in the file.

www.nxjournaling.com

 

[JohnRBaker]

You should be able to do that using KF (Knowledge Fusion).

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
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