creation of a knot in patran

[Giada89]

Hi.
I would like to ask you if someone knows how to create a knot in patran, especially what to put in ''node location list''
I have a solid but the xyz reference system is far from it, so how can I insert the coordinates at a precise point?
Should I create another reference system at a congenial point?
When I try to put values then it makes me the very small solid and I can't even turn it back and it moves without control
Thank you!:smile:

 

[volaff]

I'm sorry if I interfere, but... Did you make the solid mesh?

 

[Giada89]

Yes...
another doubt: I realized that the measurements are inc, how do you put meters or millimeters? They have already asked in another discussion but continues to remain inc. So the force is in newton?

 

[volaff]

I press that I have never used patran but another fem analysis software;
try to see also on youtube, there should be videos for using the software.

somewhere there should be the units of measures used; If the lengths are inc maybe (but I don't know) the forces should not be in newton.

 

[Onda]

to make a knot put his copulates in square brackets [X Y Z].
you can also make a new reference system and insert the point into the new coordinate system.
otherwise you can do nodes on points (geometries)
Patran does not use measuring units. therefore does not know whether the model is in meters in mm or in other.
the only time you impose the units of measurement is when geometries amounts. If you're looking for a window where you tell him the relationship between imported geometry and the data base.
e.g. if you import a model in mm and you want it in mm the ratio is 1.
if you import an inch model and want it in mm the ratio is 25.4 and so on.
If you have already imported and realize that the model is wrong you can always scale it.

 

[Giada89]

So if I want to apply a moment at a point, like 87n*mm, then in loads I have to put 87 nmm or 3,43 n*inc?

 

[Onda]

the measuring units you use must be congruent. Patran and nastran do not make any intervention on the numbers inserted.
If your model is in mm the moment will have to be in n*mm if in which the moment will have to be in pound*inch.
n*inch are not usable.
I would let you miss the Anglo-Saxon measures and use the decimal metric system.
be careful that if you use mm instead of meters, you have to put the masses in tons and the density in ton/mm^3.
This is because you have to make the forces correct. force (newton)=mass* acceleration.

I get that for a mass of 1kg equal to 0.001ton and an acceleration of 1000mm/s^2 (1m/s^2) I have a force of 1n. and everything comes back.

 

[Giada89]

I understand thanks!:smile:
only that going in preference--> geometry--> and in scale factor put meters and then apply does not go, they continue inch

 

[Onda]

but don't you first climb the whole model of 25.4 and work with the mm. without going crazy?
I think that basic, if it matters to you inch, you set the wrong measuring units in the cad from which you exported the file. in any case if you put all the geometry in a group and then stop the group from the origin of the coordinate system you are in place