% masses cumulées > 100%

[TraitCarré]

Hello,

How is it possible to get % of cumulated masses > 100%?

 

benoît

[StefanoPasquini6790]

Probably you have converted two times the same load case or you gave them a conversion coefficienr higher than 1.

Send file please.

Greetings

[TraitCarré]

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@StefanoPasquini6790 wrote:
Probably you have converted two times the same load case or you gave them a conversion coefficienr higher than 1.

I don't think so.

Send file please.

https://dl.dropboxusercontent.com/u/79282449/PASSERELLE%20PIETONNE%20PUBLIQUE_EC5%27.zip

values are different than the snapshot, but still >100%

Greetings

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[StefanoPasquini6790]

I'm sorry for my delay, I've watched your model and I found some little mistake in modal analysis:

1) why do you select the sturm check? This option increase indefinitly the iteration of modal analysis and create an error in mode n. 53

2) in the load to mass conversion you must assign the conversiont to dynamic mass instead of global mass

3) why do you choose 438 modes?

4) why do you ignore density and convert the self weight???

I've erased your modal and I've made a new one, with ten modes I've 86% of mass eccitation with 0,015 dumping (as you did) and everything will go ok.

Now I'm working by my mobile and I can't send you the modified model. Tomorrow I will send you.

Greetings

[TraitCarré]

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@StefanoPasquini6790 wrote:
I'm sorry for my delay, I've watched your model and I found some little mistake in modal analysis:

1) why do you select the sturm check? This option increase indefinitly the iteration of modal analysis and create an error in mode n. 53

4) why do you ignore density and convert the self weight???

-> 1) & 4) : I did as the Autodesk Instructor told us to... self weight and permanent load are in the same case, that's why I do this way.

2) in the load to mass conversion you must assign the conversiont to dynamic mass instead of global mass

-> right

3) why do you choose 438 modes?

-> I choose 500 as a first test, but Robot could only calculate 438.


I've erased your modal and I've made a new one, with ten modes I've 86% of mass eccitation with 0,015 dumping (as you did) and everything will go ok.

-> damping = 0.015 is for footfall analysis according EC5. I normally try to reach 90% in all direction.

Now I'm working by my mobile and I can't send you the modified model. Tomorrow I will send you.

-> thanks for helping . is it possible to send it in PM?

benoît

Greetings

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[StefanoPasquini6790]

HI, 

here is the model (I made it in 2015, I don't know your Robot version!)

LINK: https://www.dropbox.com/s/x2r3whx330f6pas/PASSERELLE%20PIETONNE%20PUBLIQUE_EC5_PasPro.rar

I've separated the self weight from the dead loads, I've erased your modal Analysis and made a new one, setted like this

Only one problem...you will never have the 90% of mass eccitation in Y direction, there are the restraints that avoid it.

Hope I help you, greetings

[TraitCarré]

Hi,

thanks for the file. it works.

90% masse in y-direction are reached when you tick "Limits -> Inactive" and choose 251 modes.

thanhs for your help.

Could you please suppress the file in your dropbox (I did so with mine)?

best rgds

benoît

[StefanoPasquini6790]

Done 

[t.sautierr]

Could you re-attach your model because the first question wasn't ansewered and it scratches my curiosity 🙂 I'll look at it.

Normaly you can't have modal mass > total mass (maybe it is because of sturm verification and if the results are squarred then you loose the sign so ....)

Thx

[TraitCarré]

Hi,

here it is : https://dl.dropboxusercontent.com/u/79282449/PASSERELLE%20PIETONNE%20PUBLIQUE_EC5%27.zip

Thanks for giving me your feeling

rgds

benoît