uniball modeling for static study.

[Manuele Rudino]

Hello, everyone! for my thesis I am doing a study of optimization of a suspension for racing cars. the software I use is solidworks premium 2010. I've been pointing out the problem that's been blocking me for days.

the suspension arms are bound to the frame by uniball (spherical joints). setting constraints for static study it is necessary to use the "advanced" section on spherical faces.

at this point selected the spherical surface affected by the bond you have the possibility to establish three degrees of freedom that are: a radial translation and the two rotations. the permissible translation is required in mm while rotations in radiants.
after setting no translation and both rotations on 6.28 I launched the solutor that never reaches a result in addition to having eternal solution times!

I tried many other combinations of values by decreasing angles without ever getting correct results. the only values with which the solutor works well are three zeros. no translation and no rotation but so the bond behaves like a fixed joint that does not correspond to reality and I do not need anything.

I also tried to replace the balls with cylinders using the "fixed cartridge" in this case you reach a result but not perfectly real.

I don't know where to beat my head, if you help me I will be infinitely grateful.

 

[Swarzy]

Hello, manuele,

provided that you posted in the wrong section (there is the appropriate cosmos section), the reason why it fails to converge could be given that you are performing a static study with possible displacement (not infinitesimal) of the parts.

Anyway:

Part analysis or together?
What kind of optimization of doing?
- What results do you mean?
If you're in the environment together, did you set up contacts?

so that we can give you a hand, if possible post the template file, or screenshots!


Hi, swarzy.

 

[Manuele Rudino]

I apologize for posting in the wrong section, I'm a poor newcomer to the first message, in the future I will see to open my eyes better... Sorry!

attached there is the simplified model of the left front suspension.
I'd be curious to know if you like me, I still have to work on it anyway.
In fact choosing which constraints and contacts you use for me that I have zero experience is a nice problem.
Don't be too careful about the studies that are already there, they're attempts that I've made messing around!

I am quite certain that the main problem is represented by the two spherical constraints of the lower arm on the frame, since I put them the solutor started to trouble.

to study the problem individually I made a simple "part" consisting of a beam with a flat end and the other spherical. the evidence I described earlier I made them on this simple model. already here the solutor jams because of the spherical alley, the only way to get a result is to set the three degrees of freedom to zero.

the study covers only the lower arm, the other components do not fall into optimization. the purpose is to find the excellent tubular section of the lower arm.
Before proceeding, I must determine which areas are most solicited.
I pulled them out of the track telemetry.

determined the most dangerous section during optimization will probably abandon cylindrical geometry. pass from a constant section tube to a variable section, so as to save material where it is not needed.

Thank you swarzy for availability ^_^

 

[Manuele Rudino]

to better understand what my problem is, I also attach the model of the simple beam that can be used to try to understand how the spherical bond works.

without any degree of freedom on the sphere the solutor works, if you try for example to allow the two spins magically does not work anymore!


ps. I have visited the cosmos section, I humbly ask forgiveness, do I have to move the discussion?

 

[Swarzy]

Hello, manuele,

As soon as I have a little time I see opening the attached files and I will let you know.

Yes, please move the discussion.


Hi, swarzy.

 

[Manuele Rudino]

thank you for the availability, too kind!
I tried to move the discussion but I don't know how to do it, I fear being the user + poor forum ahahah!
Bye.

 

[Mike1967]

thank you for the availability, too kind!
I tried to move the discussion but I don't know how to do it, I fear being the user + poor forum ahahah!
Bye.

Excuse me, but how do you move that mechanism?
to me is totally defined, at the level of couplings.


for the discussion... I think it's an admin or something.

 

[Manuele Rudino]

Bye! the suspension is blocked in the position corresponding to the base set-up, to release the movement you must suspend the three couplings called initial position 1 , 2 and 3.
there is also a coupling called straight mount if you also suspend that wheel mount.

Fortunately, I don't even have to do the film studio, I'm confined to a static study
I had to fix the model in standard position. Once I can work the solver of the finished elements it would be appropriate to do other tests in different positions, perhaps even with the steering column.