Discussion Groups

Robot Structural Analysis

Product Support
Posts: 4,445
Registered: ‎04-26-2010

Re: time history analysis

03-26-2013 07:49 AM in reply to: Rafal.Gaweda

Next run of calculations over this night (1500 increments).

Rafal Gaweda
Active Contributor
Posts: 29
Registered: ‎02-26-2013

Re: time history analysis

03-27-2013 08:57 AM in reply to: Rafal.Gaweda

hi Rafal,

did you find something interesting?

Product Support
Posts: 4,445
Registered: ‎04-26-2010

Re: time history analysis

03-27-2013 09:01 AM in reply to: dziub7

For now - no

Hopefully next set of results will be available in 10h.

Rafal Gaweda
Active Contributor
Posts: 29
Registered: ‎02-26-2013

Re: time history analysis

03-27-2013 09:58 AM in reply to: Rafal.Gaweda

OK, 10h of calculations

when i look in the acceleration results in the model you send to me:

- biggest acceleration are in nodes 116 135 374A376: all are where the cables connect to the rigid element

if we look for node 116, max acceleration is 1m/s²; in node 114=0.37m/s²

- i have to study the acceleration in node 93, where, I think, should be the biggest acceleration, (since, it is the place of maximum deformation in first mode of the modal analysis) maximum value is 0.46m/s² ; the person who studies the problem before me found: 0.15m/s².

- about the main element of the bridge: elements from 366 to 406: today elements mesure 3m, do you think I have

to divide them more?

again thank you to take time on this model!

see you tommorow...

Product Support
Posts: 4,445
Registered: ‎04-26-2010

Re: time history analysis

03-28-2013 09:34 AM in reply to: dziub7

around 50h more to go

Rafal Gaweda
Product Support
Posts: 4,445
Registered: ‎04-26-2010

Re: time history analysis

03-29-2013 03:44 AM in reply to: Rafal.Gaweda

Happy Easters

Rafal Gaweda
Active Contributor
Posts: 29
Registered: ‎02-26-2013

Re: time history analysis

04-02-2013 12:58 AM in reply to: Rafal.Gaweda

Hi,

did you get any results?

Product Support
Posts: 4,445
Registered: ‎04-26-2010

Re: time history analysis

04-02-2013 01:37 AM in reply to: dziub7

Not converged :-( starting from 625 step

As you may see from the diagram above it is still "accelerating".

Do you expect such behavior or maybe damping is too low?

Calculation started with settings as below:

expecting results in a week(?) or so.

Rafal Gaweda
Active Contributor
Posts: 29
Registered: ‎02-26-2013

Re: time history analysis

04-02-2013 04:51 AM in reply to: Rafal.Gaweda

Hi RG,

i don't understand why its not converged, first time when you send me the model,

you find results.

I see the diagram is still accelerating, I expect such behavior during several time, but should

stabilize after this time, Im looking for the value when it is stabilized. I tried the same analyse during 30s, and it still accelerating, but not much.

Im doing it during 50s right now but calculations take a very long time!!!

concerning your setting: time step of 0.002s may be too long to calculate, don't you think?

Product Support
Posts: 4,445
Registered: ‎04-26-2010

Re: time history analysis

04-02-2013 05:17 AM in reply to: dziub7
Stephane,
i don't understand why its not converged, first time when you send me the model,

you find results.

I see the diagram is still accelerating, I expect such behavior during several time, but should

stabilize after this time, Im looking for the value when it is stabilized. I tried the same analyse during 30s, and it still accelerating, but not much.

As far as I undestood you \ we got very high accelerations in this model that's why we had to dense calculation steps to get maybe more accurate results.

UNfortunatelly such model did not converge.

Im doing it during 50s right now but calculations take a very long time!!!

I hope you are calculating it with Pdelta.

concerning your setting: time step of 0.002s may be too long to calculate, don't you think?

Do we have any choice? This is the setting which MAY lead us to convergence. We will see.

Rafal Gaweda