Solidworks Simulation Study Explanations

Simulation Generality
1

Hello

I would like to make a simulation of an assembly of two aluminum parts, held together by rubbers, the upper part of which is fixed by screws to a frame and the lower part fixed by screws at a load of 11kg. Image below (without screws, frame or load).

So far, I have created a virtual wall (representing the frame) at the top of the room above. To this one, I attached 4 anchor bolts (blue arrows on the top piece).

Subsequently, to represent the load, I created 4 countersink screw type connectors to which I added an axial force corresponding to 1/4 of the load (blue arrows on the bottom part). I already have a doubt about the correctness of this reasoning, what do you think? What else should I do?

Finally I added gravity (red arrow), then I tried to run the simulation, but lo and behold, at that moment I got an error message: "Improper or no target defined for contact element xxxx". However, the contacts between the rubbers and the 2 aluminum parts have been (in my opinion) correctly defined (as tight adjustments) and are no longer detected as interferences... I think the mistake comes from the anchor bolts...

Summary of the study:

Error message:

 

2

Hello

 

Your problem is not simple.

You would have to post your ASM (with the pack and go function or the equivalent function in your version)

If I understand it fails from the beginning! That is to say, from the mesh.

For the rest, we'll see later, but I have two small ideas because it seems to me that there are probably errors in the intention.

Kind regards

3

Hello

Thank you very much for your answer. From what I've seen, I think it crashes right after the meshing operation.

Here is a link to download the zip file of the pack and go export, I hope everything is there.

https://transfernow.net/42hv8az01kkg

Kind regards

4
  • Good evening
  • I'll look at your file tomorrow if possible.
  • Kind regards
5

Thank you

6

No ideas?

7

ouch! I forgot you

I just looked.

Your choices are not consistent

1°) We only have the impression that what you want to test are on the one hand the anchor bolts and also the countersink screws which is absolutely of no interest.

2°)  Your study contains no charge except gravity, the meaning of which is in reverse. It should be specified where the battery is located (is it a ventilation battery or one that delivers current)

2bis) Nothing about the CG of the charge or the number of N.

3°) We wonder how you have (or will you)  managed to fit your silent blocks into the bores.

3bis) you have made all your objects together, so you won't see much, you have to put the connectors in the right places.

4) You say nothing about the nature of the vibrations or horizontal and vertical displacements.

Brief! Nothing can be done without detailed contextual information

Kind regards

1 Like
8

Hello

Thank you for your answer.

1) I don't want to test the anchor bolts, but simply indicate how the assembly is fixed (fixed by bolts to a frame represented by the virtual wall and the anchor bolts), but I'm probably doing it wrong. As for the countersink screws, I would simply like to point out that the load force (support for a lipo battery of about 3kg + carrying a flight of sensors to arrive at a maximum charge of 11g) is transmitted through these screws (which I consider infinitely more resistant).

2) Gravity is indeed upside down, since the piece will be mounted upside down as well. For the battery, it is centered on the support, which is itself centered in relation to the screws. So I wanted to define a force value that would be taken up by the screws in an equitable way, but I think I'm wrong in how to simulate this effectively.

3) The "silent blocks" are actually simple rubber whose deformation is more than enough to insert them into the holes without (too much) difficulty. They are also recovered from an existing system on which they were already mounted tightly and I was able to test the principle by quickly drilling an aluminum scrap of the same diameter.

3bis) Thank you for the information, I will look into the subject.

4) There is no displacement, since all the components are mounted fixed in relation to each other. On the other hand, there could be various vibrations created by eight small electric motors located on top of the frame.

Finally, from a contextual point of view, this is a European project for measuring gas concentrations by carrying sensors on octacopter drones. The frame is therefore the drone with its hardpoints, the charge is simply the battery and the sensors.

9

OK I'll look and come back to you :-)

10

Good evening

I am attaching a Word document so that you do not have too long a text here.

As for what follows in the .doc: I ask you to take it positively and as remarks from people with a little experience and not as criticisms.

If you are in engineering schools, it means that you already know a lot of things, but also that you still have a lot to learn. As you read the following, I hope it gives you some positive indications for improving your design.

I remain at your disposal to discuss each point. ;-)

Kind regards


remarque_de_conception_simulation.docx
1 Like
11

 

 

12

You will find the answer in the attached Word doc.

Good luck and tell us if you still want the simulation because with what we know now we can start from a very simplified model. If you are not required to produce calculation notes, then the simulation is not of much interest.

But we're here to help if you need to!

Kind regards


remarque_de_conception_simulation_-_reponse_2_.docx
1 Like
13

Damn, I hadn't seen your answer and I apologize for this late response.

I will take into consideration your remarks, which are very instructive.

- First of all, I'm going to follow your idea, and have the turntables soldered (after discussion with the workshop manager who will have the part made, he tells me that it would be much easier for him indeed). So, I'm also going to split my part in the SW assembly.

- I hear your remark about the diameter of the bore and I will therefore create a part without a tight fit.

- Unfortunately, I don't have a spare stamp to carry out a test... On the other hand, I still think I will keep the 2x6 elastomeric pads because for safety reasons I prefer to see them in good numbers, even if it means losing vibration attenuation.

- I take note of the idea of the drill with sandpaper to make the chamfers, and to be honest it was a solution that I had also considered.

- Far be it from me to neglect the workers, who are always at the origin of the realization of things and often of good advice, however not being French I was not familiar with the names of the diplomas in your country.

I'm going to continue this simulation story, because it allows me to justify my achievements in a clean and technically interesting way, and incidentally it allows me to discover a part of the software that I didn't know well.

However, I would have just liked to know two things:

- Does the attachment to the frame (drone) of my assembly simulated by a virtual wall anchor bolt represent reality? What is the difference with the consideration of bores as fixed geometry? (apart from the resistance of the screws).

- Is it possible to tell solidworks that the load (the 11kg) is transmitted through screws? Or should I create a sketch of the size of the washer and apply the load to it?

Once again, thank you again for your precise help,

Kind regards.

 

 

 

 

 

14

Bam!!! Another self-congratulation.

It's the author who has the best answer, probably because he has the last word.

Pov' Ducros!

1 Like
15

Damn, I mistakenly clicked on "this answer solved my problem" when I wanted to edit myself and I couldn't go back... How do I remove this?