Problem with the application of force

Hi all

I want to have an answer to a problem that I don't really understand.

When I do a simulation, the surface of application seems to change the result. My question is simple, if I take the example of a beam resting on an axis, if I put the 5000N on the entire beam the result of the stress is greater than when I apply the force on the end.
On photo 1 we see the assembly with the area I'm interested in in in the red frame

In photo 2, only the insulated part on which I want to check the constraints

In photo 3, when I apply the force to the entire UPN

In photo 4, when I apply this force at the end of the UPN

I have the impression that Solidworks does not consider the UPN (and the clevis that is welded to it) as a whole that only moves in the requested directions


photo_1.bmp

Hello

Unless I'm mistaken, I only see one photo in your post

We need to see the different vectors you use  to help you.

In your example, only the upper beams (the one that supports your top) are to be taken into account.

The force on the axis of the red area changes all the time as the elevation increases. The maximum effort is obviously when  everything is down. SW takes care of everything, it has to come from the way you take it.

Kind regards

Indeed, sorry I didn't see that there was only one published...
That's why my tests are done especially when the assembly is in the lower part.
 


photo_2.bmp

On this one there is therefore a test


photo_3.bmp

And this one is when I apply the force only on the tip of the UPN


photo_4.bmp

Hello

First of all, there's no point in putting the effort on the UPN if it's the axle and its attachment that you want to test

Your efforts must be in the axis of the UPN (parallel to the face of the end of the UPN because the forces are strictly axial. Careful! but you saw it :-)  the overall forces are divided by two by four compared to the load on the plateau.

There is an excel sheet that calculates all the efforts. This is very useful to know the true forces on each axis before doing the simulation

Crodally

 

 

Hello

It is true that putting the UPN in place does not really make sense except to have a sense of force. As for the loads, the table is intended to lift 2TB hence the 5000N on each of the UPNs of the two scissors.

The question was not really about the "concrete" case but about the fact that the same force applied at two places of the UPN does not give the same force on the axis. (It will be 42CD4T I don't worry about the axle) It was especially for the two screeds.

I would like to know how solidworks calculates, it does not seem to consider that the welded assembly (the UPN and the clevise) can only move by the indicated forces. If he ever considered the UPN as fixed on the other side, the force should be greater when I apply it only  on the tip of it. Whereas here it's the opposite.
I'm sorry, I don't think I can express my incomprehension about the result obtained by Solidworks.
 

 

No problem!

but try to put your strength parallel to the end of the UPN it will be fairer anyway

If you put on the SW edge, consider that all the force is concentrated in this area exactly, it applies it to a smaller surface to put it another way.

Anyway in real life the efforts according to the axis of the UPN

If you do the full simu with the charge only on the tray you will see how your UPNs blaze.

Kind regards

Ok, thank you for your answers,

 

Kind regards