Solidworks simulation pivot link

Simulation Generality
1

Hello

I have a problem with my simulation.

I have the assembly of a stem with 4 pivot links.

When I start the calculation, despite the drawing of axis connectors in the appropriate places, the results given do not take into account the pivot links...

I would like to point out that I have, of course, checked that there are no other interdependent contacts between other elements that could prevent rotations.

I read on the Solidworks help: "If you run an analysis (e.g., with SolidWorks Simulation), the results and reaction forces are associated with the pivot stress (and not a specific coaxial or coincident stress)" when I thought that the assembly stresses had no bearing on the simulation since you have to recreate the contacts...

Thank you for your help.


potence.jpg
1 Like
2

Hello

Do you have a view of your problem? I admit that I'm not sure I understand it well.

 

Afterwards, it seems to me that the help also tells you that the assembly constraints are not taken into account.

1 Like
3

Here is a tutorial that allows you to optimize your part design according to the predefined loads

 https://m.youtube.com/watch?v=s8jW_UbOC6o

FYI, avoid republishing your question for additional information following an answer that you have been asked for, it will not be taken into account in the feed flow

so @ chamade apart from coming back on the wire will not know how to inform 

@+ -))

 

2 Likes
4

Hi @ Davond

After some research I just found a tutorial that I think can help for your study 

https://m.youtube.com/watch?autoplay=1&v=iNODON-AwD8

give us news and to tell us where you're stuck

but I think with the info cited above you should get out of it

@+ -))

5

Hello and thank you for your help.

You can click on the "gallows" link in my post that shows my project.

In fact, I have to apply a force at the end of my stem. This is more or less balanced by the counterweights on the rear.

I have my 4 pivot links indicated.

As a result, only the threaded rod with nut passing through the welded lug near the mast of the stem supports the load by acting as a low stop.

My problem is that, a priori, I can't integrate my pivot connectors since by redoing my simulation without this famous threaded rod, I have the same results...??? when, logically, nothing prevents my assembly from pivoting!

Thank you for the videos. I'm looking in more detail to see if it can help me.

1 Like
6

In fact, see this image (more telling).

Thank you


nouvelle_image.jpg
1 Like
7

Have you already identified your center of gravity in the first place?

since it seems to me that your jack that allows you to change the angle 

what is the purpose of the 2nd pivot link on the U of your stem where it is badly placed on your last image

When you move your arm high in your assembly, nothing crawls

what version do you have of SW

@+ ;-))

8

See this tutorial

http://www.lynkoa.com/tutos/3d/table-elevatrice-simulation-etude-statique

 

@+ ;-))

1 Like
9

Thanks for the link.

So, it reassures me because that's exactly what I did... Connecting axes to my 4 pivots.

This mechanical principle allows the arm to always remain horizontal.

Normally, a cylinder handles the load but, in my case, I want to see the reaction of my threaded rod from below (stop) at 200 kg without the cylinder holding back.

But in this case with a load of 200kg simulated at the end of my arm I should have the threaded rod underneath that takes all the load and that should flare up, right?

10

if the jib doesn't "fall" without the stop, wouldn't there be faces in contact that SW has fused automatically?

Can you post images with distorted of the 2 results with and without the rod to see at what level the movements are blocked?

 

After that, what exactly are you looking for results? Do you have to go through an FE simulation?

1 Like
11

Hello

Simulation only allows you to perform calculations if your model is TOTALLY balanced. In practice, if you don't block the movements at the end of your stem (where the counterweights are), it's almost impossible for Simulation to have something balanced because your counterweight won't be able to perfectly balance your effort (so the calculation should diverge because with each iteration of the calculation your stem will move slightly).

If the pivot doesn't work well, you can try the contact management between the axis and the pivot (be careful, it's very long and given your model, the calculation may crash).

 

12

OK well understood.

So, I redid my calculations on my subassemblies and it gives me satisfaction.

Thank you again for your help.

13

Hello

 

To detect problems with connections, movements or contacts, you can also use the low stiffness and/or inertial relaxation options in the properties of the study (calculation).