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Tau formula

21 REPLIES 21
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Message 1 of 22
jo2ny
1282 Views, 21 Replies

Tau formula

hi,

i got this design result for one of the beams in my model.

i find it weird since the Vy,Ed value is very small.

can anybody provide the extended calculation for Tau,ty,Ed, and how it comes to that value 1.45 ?

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21 REPLIES 21
Message 2 of 22
Artur.Kosakowski
in reply to: jo2ny

Please check the torsion (stress due to torsional moment) in this bar rather than shear.

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.



Artur Kosakowski
Message 3 of 22
jo2ny
in reply to: Artur.Kosakowski

You were right. It was from the torsional moment. I checked it and i got the 1.45 value.

Thanks.

 

One more question.

In my attempts to find a solution, I opened the detailed design window.

I set some stiffners, thicked all the verification boxes (web stability at shear, at compression, etc.)

Then I hit the Calculation button and got the results. After that I did some modifications to the stiffners ( increased the thickness ). When i tried the do the calculation again, the mouse cursor changet to "working" but when in changed back to normal i didn't get the results anymore.

Any ideas why?

 

Message 4 of 22
Artur.Kosakowski
in reply to: jo2ny

I would need the step by step description of your actions or a movie (plus the model) to run some test and try to investigate the situation you described.



Artur Kosakowski
Message 5 of 22
jo2ny
in reply to: Artur.Kosakowski

I attached a picture with the steps I did (numbered from 1 to 8).

I tried to attach the model too, but it seems the zip file it's too large 😞

Message 6 of 22
Artur.Kosakowski
in reply to: jo2ny

Is your file saved with or without results? Try to save it under a new name selecting rtd without result and then compress it. In addition copy the spacing of ribs from the field and paste it on the forum so that I can see it in full. Thank you.



Artur Kosakowski
Message 7 of 22
jo2ny
in reply to: Artur.Kosakowski

I couldn't make it smaller. Probably there were results stil in the file and i didn't know how to discard them.

I selected all the structure and used the "Save substructure" button. Hope that's fine.

 

I set the stiffener distances as it followes: 0.00 ; 3.00 ; 6.00 ; 9.00 ; 12.00

(meter) absolute distances.

the beam is 12 m long

Message 8 of 22
Artur.Kosakowski
in reply to: jo2ny

I have followed the steps you described but in my case the results are correctly displayed after making changes to the location of the stiffeners and their thickness. Try to close Robot  and then load the file again and check if you are able to run the detailed analysis.

 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.



Artur Kosakowski
Message 9 of 22
jo2ny
in reply to: Artur.Kosakowski

That's what i did.

And it worked agan one time, then no more.

I maybe should try reinstalling.

 

Message 10 of 22
Artur.Kosakowski
in reply to: jo2ny

Could you make a movie that show exactly all your actions please? I'll try to follow.  Perhaps there is something that we do in a different way and the movie will help me to find the reason.



Artur Kosakowski
Message 11 of 22
jo2ny
in reply to: Artur.Kosakowski

I could record a movie. You mean using a desktop recording tool, right? Could you recomend me one?

Or is there another way?

Message 12 of 22
Artur.Kosakowski
in reply to: jo2ny

Yom may want to look at http://www.techsmith.com/jing.html



Artur Kosakowski
Message 13 of 22
jo2ny
in reply to: Artur.Kosakowski

Hello,  sorry for the delay.

I captured a footage of how i modify the values. This time it took a little bit more to make it not work, but other times i took only one modification.

There are two parts of the footage. The first one you may want to skip since it contains the calculation of the model.

Message 14 of 22
Artur.Kosakowski
in reply to: jo2ny

I'm sorry but the movies seem to be corrupted. Could you check them please?



Artur Kosakowski
Message 15 of 22
jo2ny
in reply to: Artur.Kosakowski

hello,

i managed to record a footage.

here it is.

apparently it happens when I unthick some calculations and then thick them again ant then try to run the calculation

here is the file http://dl.transfer.ro/transfer_ro-07mar-d0f10145eb1f3d.zip


Message 16 of 22
Artur.Kosakowski
in reply to: jo2ny

As you probably expected nothing like this happens on my PC however I noticed one strange situation on your movie that I would like to confirm. After opening the detailed analysis window you have all check boxes for verification marked. Then you switched off 3 bottom one and the note was opened. Then you closed the note and in the detailed analysis window only the last check box remained unchecked. Were the other two automatically marked on when you closed the note or you made his change but this part is not shown on the movie?



Artur Kosakowski
Message 17 of 22
jo2ny
in reply to: Artur.Kosakowski

No, I thicked the two boxes after i closed the calculation window. They were not automaticly thicked. It's not shown due to low fps i guess. I remember that I clicked very quickly and the said to myself afterwards that I should do it slower.

 

As you saw, neither in may case, it doesn't do this "not showing window" all the time. And I noticed that it never happens the first time i run the calculations. Maybe it's because of lack of resources (old PC), i don't know.

Anyway it's not very bothering, so if you consider it an isolated case I think we can close the post 🙂

 

If you have any other ideas regarding the subject, or if you would like another movie, I'll be glad to help.

 

 

Message 18 of 22
Artur.Kosakowski
in reply to: jo2ny

lack of resources (old PC),

 

Is it 32bit OS? If 64 what is RAM size?



Artur Kosakowski
Message 19 of 22
jo2ny
in reply to: Artur.Kosakowski

64 bit OS

3Gb RAM

 

Message 20 of 22
Artur.Kosakowski
in reply to: jo2ny

3GB RAM for 64 bit OS may definitely be a factor Smiley Happy



Artur Kosakowski

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