Force impact ball

[MarkosMark]

I want to test the impact of a ball on my construction, but I don't know how to modulate this.
For example I want to simulate a ball that hits my model with 200N. How could I do this? Because this needs to be a short dynamic force instead of continuous static force.

I'm using NX 9.0 (but I also have NX 10 or 7.5 if needed) with nastran


[sub]and one small other question. I don't know if I should start a new thread for that one because I think it's something done easily. I want to export my model to a .step file. But I can only find the option to export it to .stp. I need to deliver my part as .step file. I already tried to just rename it to .step but then they can't load my part. Is there an option to export it as .step?[/sub]

 

[Tuw]

Hi MarkosMark,

Please find the attachment at discussion thread below:

https://community.plm.automation.siemens.com/t5/NX-Nastran-Forum/Contact-in-NX8/m-p/314809#U314809

Kind regards,
Tuw

 

[MarkosMark]

Hi Tuw,

I think my knowledge is limited, because I don't know how to implement it in my problem. The sphere (ball) I want to model isn't forced by gravity in the vertical direction but with an initial speed of 14 m/s horizontally (friction and gravity neglected). It would be nice if I can actually model it as a sphere what hits my model. But I first was thinking of a force load that increases from 0% to 100% and back to 0% in a given time. I did this in the past (with an older version of NX) but I can't seem to find how i did this and how to do this in NX9/10. And I don't know how this is actually called, so I don't know what to google.
I have seen the option to couple the force to an excel table, but I don't know how to use that option and if that's the option I want to use.

 

[Naffoussi]

For the second question .step = .stp

Seif Eddine Naffoussi, Stress Engineer

http://www.Innovamech.com

33650 Martillac û France

 

[Tuw]

Hello,

To define a force load with respect to time, simply click on the Force Button.

Click on the circled location to access the table input.

Click on the circled location to define the time axis.

If you want to use Initial Velocity instead of Force, then you can use the Transient Initial Conditions button at Constraint drop down window. You also can use field table to define the velocity with respect to time, same manner as above.

Regards,
Tuw

 

[MarkosMark]

Thank you, I indeed found out I can manually add the table values in NX/Nastran without using excel. It didn't work with excel (or I did something wrong). But I think I'm still doing something wrong. I have added my simulation files. I included 3 solutions in the file. The differences are:
static force: Force is constant with 420N
dynamic force: I used a table to define the force (0,1 / 0.01,200 / 0.02,350 / 0.03,400 / 0.04,420 / 0.05,400 / 0.06,360 / 0.07,320 / 0.08,260 / 0.09,160 / 0.1,1)
static force (1N): Force is constant with 1N (like the start/end force of the dynamic force)

I don't get the results I hoped to get with dynamic force. The results are the same as for a static force of 1N. But I'm interested in the maximum magnitudes. Am I doing something wrong? I also tried other solvers but then I have the following problems:

SOL106 no surface-to-surface contact

SOL601 fails:
SOL601 Advanced Non-Linear Static

T O T A L S O L U T I O N T I M E (SEC) . . . . . 218.65
MEMORY USED BY THE SPARSE SOLVER= 0.0mw ( 0.0mb)
TOTAL MEMORY USED BY THE PROGRAM= 34.4mw ( 275.2mb)
Checked in NX Nastran license feature nx_nas_advnlin_dsk.
*** END SOL 601 ***
*** FATAL ERROR: SOL 601 DID NOT FINISH SUCCESSFULLY.
*** ADVANCED NONLINEAR EXIT CODE 0 ***
*** ISHELL PROGRAM 'NXNA' COMPLETED ***
^^^ USER FATAL MESSAGE
^^^ ERROR IN ADVANCED NONLINEAR MODULE 0
^^^SOL601 FAILED

SOL601 Advanced Non-Linear Transient

T O T A L S O L U T I O N T I M E (SEC) . . . . . 230.72
MEMORY USED BY THE SPARSE SOLVER= 0.0mw ( 0.0mb)
TOTAL MEMORY USED BY THE PROGRAM= 44.9mw ( 358.8mb)
Checked in NX Nastran license feature nx_nas_advnlin_dsk.
*** END SOL 601 ***
*** FATAL ERROR: SOL 601 DID NOT FINISH SUCCESSFULLY.
*** ADVANCED NONLINEAR EXIT CODE 0 ***
*** ISHELL PROGRAM 'NXNA' COMPLETED ***
^^^ USER FATAL MESSAGE
^^^ ERROR IN ADVANCED NONLINEAR MODULE 0
^^^SOL601 FAILED

SOL701 no surface-to-surface gluing

(in my files, there are some parts (polygon geometry) I don't use for the simulation. So you can ignore those parts)

 

[Tuw]

Hi,


For all 3 runs, you are using the same solution, which is Sol101, linear static. If you plan to use this solution, then there is no meaning to input a graph as below as the loading.

If you plan to use the graph load, then you should choose Sol106 or other dynamic solutions.

If you plan to use Sol101 and still produce a difference between your solution "dynamic force" and "static force", then you should just input the highest magnitude (from the graph) as the loading condition. You will get a static representation though.

I am not sure why you cannot use Sol601 and Sol701, probably due to license availability. You need to check with your authority for that.

Regards,
Tuw

 

[MarkosMark]

I tried SOL106 but I can't apply my surface-to-surface contact in that solution. Is there an alternative for surface-to-surface contact in SOL106?
If I change the surface-to-surface contact to gluing, the results for force 1N is the same as the dynamic force in SOL106.

SOL701 doesn't work because I can't apply my surface-to-surface gluing there.

And for SOL601, I have no idea. I have the proper licences available, I also tried this in NX10. Can it be caused by my 3D mesh? I should probably use 2D mesh? I have no idea how to use 2D mesh. I tried a few time 2D mesh but it doesn't work then at all (faulty mesh error)


What more option do I have otherwise? Because it's a spike load, I can't use a static load right? The stresses and displacements are a lot bigger when this load is continuously instead of just a spike load of a short period

 

[Tuw]

Hi,

If you are simulating impact load, then you have option to use Solution 103 Response Simulation.

Solution 601 should be able to run, if you can run on Sol701.

For impact simulation, Sol106 is not suitable because it is a quasi-static solution.

As I said, you may try on Sol103RS, or Sol601129. Sol601106 is not suitable because it is quasi-static as well.

About your 2d meshing problem(unable to mesh issue), I suspect it is due to dirty CAD error. Use NX CAD to clean it up (command such as optimize face, examine geometry, etc)

 

[MarkosMark]

Thank you! This looks more like what I'm looking for.

SOL103RS: I don't really understand what all the results are. Mode 1 till 10, what does this mean? Sort of frequency response? Should I only watch the Distributed Attachment Mode 1?
And this Distributed force, when I for example load the displacement and play the animation. Shouldn't I need to see an animation with increasing displacement until it hits its max load (420N like in the graph above) and then return to its 1N loaded displacement?
What does this displacement show (without animation)? The maximum displacement?

SOL601-129: I'm still getting an error when I try to solve this one.

I have attached the simulation with SOL103RS and SOL601-129

 

[Tuw]

Hi,

About Sol601129, you need to input a time definition, as indicated by pictures below. This is your primary error.

About Sol103RS, please try to read the NX Documentation. In general, you will use the mode results for further analysis (response). After you achieve the mode results, proceed to create add on analysis as indicate in figure below.

 

[MarkosMark]

I’ve simplified my problem, maybe this will help finding the way to get the results I’m looking for.

1. Fixed constraints
2. Fixed constraints
3. Surface-to-surface contact
4. Force load

These are two non-united beams. They are fixed at the face in 1 and 2. I’ve made a surface-to-surface contact at point 3 manually with two regions. And at point 4 I’ve applied a time depended force like applied before.

This force is created by defining the force in steps between 0 and 0.1 sec:
Time (sec) | Force (N)
0.00 | 1
0.01 | 200
0.02 | 350
0.03 | 400
0.04 | 420
0.05 | 400
0.06 | 260
0.07 | 320
0.08 | 260
0.09 | 160
0.10 | 1

I would like to see what the maximum values in my model will be. This can either be by just showing the maximum values over the given period/solution. Or just seeing the results step by step (at t=0, t=0.01, …, t=0.05, …, t=0.1)

Does this makes clear what I'm looking for? What solution type should I use for this?

(People around me are saying just to use a static force, but the results won't be the same. The displacement/stress will be totally different if I just apply this force for a short period, or I apply this force continuously)

 

[Tuw]

Hi,

Please find my reply at your other thread.

https://community.plm.automation.si...Dynamic-force/m-p/317183/highlight/false#M574