STATIC SIMULATION - Anchor bolt

Hello

I perform a static simulation of a metal structure in S355. I want to get the forces in the connectors (anchor bolts)

This structure is welded to a square sole of 25mm thickness . This sole is saddled to the ground via anchor bolts .

To make the calculation easier, I cut my structure 300mm above the ground, I applied a mark in the center, then I applied a load/mass remotely by selecting the mark and the top face (cut) of my structure to distribute my load case evenly.

For the anchor bolts, there are 4 of them. I used the virtual wall feature to create these bolts.

Once the calculation is started, I get my forces in my anchor rods but according to my logic, two of my rods should be subjected to the same axial forces, but this is not the case.

 

Do you have an idea for my problem?

 

Thank you in advance.

 

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Hello

Can you post images of your room and your simulation, especially the parameters and the remote loading. 

Without more information, it is impossible to say anything: especially in simulation where the parameters are very structuring

Please also specify which version you are using

Kind regards

2 Likes

Hello

Here is attached an image of my simulation.

I am using Soliworks 2020 SP0.1.

Remote charging: 

On X: 10271 N

On Y: - 7828N

Moment on Z: -109438 N.m

 

If you need item, don't hesitate.

 

Kind regards


capture_part.png

Hello

I think you have simplified your model a little too much to have a representative simulation.

The thinks that the remote mass load is way too low to reflect reality unless your room is wall-mounted and the main load is down.
In addition, confirm to me that you did not only take the edges to fix the ground from a distance. The resistance overshoots on the sheet of your dodecadone seem to indicate this. It would be better to create wider areas with interior dividing lines to the volume.

I don't see the sense of gravity, which is mandatory for remote charges.

Anyway, let's get back to our sheep and the onions that keep them.

I assume that you are only interested in anchor bolts.

The first thing to do is to make a much finer mesh
Check that you have prestressed the bolts

If your part is welded on the soleplate then put before the simulation of the radii outside which will represent the welds. This will remove all or part of the tension in the corners and the deformations of the sole because we can see that  the rear bolts seem unstressed, which is curious.

Look at your simulation in section to do so in results, click on result and select "design dissection" and there you will see the most stressed areas in depth.
You can use the slider to modulate to see the most or less loaded areas.

Because often you have surface tensions that do not exceed one mm in depth.
The deeper it is red, the more it sucks.  ;-)

One rule: don't panic too much if you see red and never show the boss raw results with  red.

Do not forget also in the results of the requested the safety factor because for your application it is the most important if you do not want to receive the hut on the dog's head.

Once these operations are done we will see for the rest ;-)

Kind regards.

PS: I hope I don't shake you too much with my remarks ;-)
I don't know you!  ;-)
But know that I am benevolent, even if I avoid letting things pass by by not responding to the bare minimum of the request. We're between PROs after all.

 

 

3 Likes

Hello

Thank you for taking the time to answer my problem.

 

My structure is fixed to the ground. I confirm that I selected the face and not the edge.

That's right, I didn't put gravity, I applied the force weighing on the Y axis.

I did not apply preloads in the anchor bolts, because it was apparently not necessary in my case.

I now start the calculation with:

A thinner mesh, as well as a chamfer to symbolize the weld, and then I added gravity.

I follow your advice, I add a minimum tightening torque on my anchor bolts .

 

PS: Not at all, I listen to your precious advice. Are you absolutely right;)

2 Likes

Result of the calculation:

The forces in the anchor bolts are almost equivalent. 

You have solved my problem, thank you for that!

Last little question: 

The anchor bolt has two types of connection: Rigid or distributed. In what case do we use one or the other?


076319-part-statique_1-connecteur-5_ok.csv
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Now you just need to close the discussion 

selecting the answer that solved your question 

@+

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Hello@rmyat

You are referring here to a novelty of the twenty-twenty.

Distributed coupling allows the faces attached to the pin and bolt connectors to warp, resulting in a more realistic representation of a connector's behavior. Distributed coupling for axes and bolts is available for linear static studies only. (source Solidworks)

In other words! When two parts are joined together, here a bolt in contact with a part, there is a kind of creep that creates microscopic slippage: since they are two separate masters, molecule speaking , if we consider that the two assemblies are totally rigid, then there is no deformation between the nodes of the part and the bolt since it is as if you had a single part. With this new function, it is possible to see the deformations that occur at the last knots in contact with the bolt and the workpiece. In theory, on a single bolt you could see the very beginning of the loosening.

This feature already existed but only for remote charging.

Kind regards

 

PS: If we helped solve your problem you can close the topic

3 Likes

Thank you again for your great help.

Have a nice day

Kind regards.