Hello.
I am trying to simulate dynamic effects due to the braking of a rotation movement, considering the rigidity of my structure using static position and Force Balance Analysis.
Using the prototype, or a similar machine, we measured the deceleration at point 2.
I'd like to apply forces to the center of mass of each body and correct the magnitude of deceleration according to the radius, in a parametric procedure, so I can easily simulate several positions.
We know this is not 100% accurate but is good enough for our application.
Force 1 = Acceleration point 2 * R1/R3 * Mass body 1
Force 2 = Acceleration point 2 * R2/R3 * Mass body 2
Force 3 = Acceleration point 2 * R3/R3 * Mass body 3
Strategies to parametrically change the magnitude of Forces:
Option 1:
R1 = using a Measure of Position inside Mechanism of point 0 to the rotation point
Problem: The analysis does not run. I don't even receive a error message. Nothing happens.
I believe this is happening because first Creo need to run an analysis in order to create the value of R1, only then would be possible to calculate Force 1.
Option 2:
Create the FORCE 1 inside relations of the assembly:
FORCE_1=ACCELERATION * DISTANCE:FID_172 / DISTANCE:FID_171 * WEIGHT:3
Then, use "FORCE_1" as the constant of the Force inside Creo Mechanism.
Problem: The magnitude is only corrected after I regenerate the model for every position.
Procedure: Run Force Balance Analysis to set the position, regenerate the model to correct the magnitude of Force 1, then run the Force Balance Analysis again with the corrected.
Is there any way to make this works properly in Force Balance Analysis without the need of manually regenerate every time or without use MODS license?
I don't want to use Dynamic Analysis to avoid the dynamic effects caulculated by Creo.
Thanks!
1 ACCEPTED SOLUTION
Accepted Solutions
That was actually my misunderstanding. MODS/BMX vs MDO.
Did you try using all mechanism based measures like this?
That was actually my misunderstanding. MODS/BMX vs MDO.
Did you try using all mechanism based measures like this?
Hello, again!
Perfect. It worked. Thank you, very much!
Note: I tried to go this way, with a slight difference. I did the equation of the force inside the Measure and used Function type Custom Load and selected the measure Force.
This is probably why it didn't work.
Could you, please, help with one more?
For my next step, I'd like to create the wind forces.
If I do this same procedure that you showed above, I would need the cross sectional area of a few components.
Do you have any idea how to make available a component parameter inside the Variables list of Mechanism Measures?
And can this parameter come from a subassembly?
Thanks!
Do relations work for this? I am guessing it has the same problem with needing regeneration that you want to avoid?
If its really simple shapes maybe use multiple "position" measures to have mechanism calculate the area like height x width.
Have you tried changing where the relations reside (Assembly/Part/Feature/Sketch)? I usually mess with this when I have to regen a Creo Cad model twice to get it fully updated.
Hello!
- Yes, I would have the same problem of regenerate again, for every position. See below.
- Use positions and create equations for area would not work. Some geometries are too complex, and this would lead considerable deviations.
For lateral winds, the projected area does not change. This strategy of using it as a Constant Function Type would work properly.
But, for rear wind, depending on the angle of the mechanism, the projected area would change.
FORCE_WIND_REAR=AREA*SIN(ANGLE_ALPHA)
So, for this, I need to recalculate the SIN(ANGLE_ALPHA) for every position.
I could use the area as a constant number and use the User Defined Function Type and ANGLE_ALPHA as only variable, as you have suggested for the other case, but then the engineer would need to update mannually the areas. I don't think this is practical. That is why I would need to make available the parametric measure of area inside the Creo Mechanism.
Thanks!
Hello, @SweetPeasHub.
I discovered how to do it.
Again, simpler that I could imagine.
Inside Relations, create a Parameter using the saved Measure Feature.
While adding the Motor, for example, inside the Edit Expression click on "Insert constant from list".
Add a new line and select the previously created Parameter and finish editing your Expression.
Notes:
- During Selection, only the Parameters of the Assembly are available. The filter does not allow to change to parts, features, or another levels.
- This also works while creating a Measure.
