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#1 2019-02-09 08:38:59

nirmaljoshi
Member
From: Japan
Registered: 2018-10-12
Posts: 152

DEFI_LIST_INST or LIST_REEL for NL analysis & convergence issues

I found that some people are using DEFI_LIST_INST while other are using DEFI_LIST_REEL for Non-linear analysis. Till now I have been using LIST_REEL because its syntax is easy to understand.

1. Does it makes a difference while using DEFI_LIST_INST instead of DEFI_LIST_REEL for Non-linear analysis? Which one is more appropriate in case of analysis of reinforced concrete?

2. Additionally, there are other DEFI_LIST which are basically doing the same thing i.e. creating a series of number. What is the main purpose of so many types?

Last edited by nirmaljoshi (2019-02-11 09:24:29)

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#2 2019-02-09 13:42:25

Anirudh
Member
Registered: 2017-09-11
Posts: 251

Re: DEFI_LIST_INST or LIST_REEL for NL analysis & convergence issues

Hello,
LIST_INST incorporates time step refinement algorithm based on a number of criteria, such as the residual in RESI_GLOB_RELA. LIST_INST takes LIST_REEL as input.
If you use REEL in STAT_NON_LINE, only the given time steps will be used for calculation. The code stops if it cannot converge on REEL. On the other hand using INST, the code tries to divide time step as per the settings and perform recalculation.
You can also manually provide time steps of computation through LIST_REEL.
You can try running some testcases as well as go through related documentation and work by others .

Anirudh

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#3 2019-02-11 04:32:57

nirmaljoshi
Member
From: Japan
Registered: 2018-10-12
Posts: 152

Re: DEFI_LIST_INST or LIST_REEL for NL analysis & convergence issues

Thanks for reply.

Which command should i use to  continue the calclation even when convergence is not reached?

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#4 2019-02-11 08:58:18

GPSalachs
Member
Registered: 2018-03-10
Posts: 177

Re: DEFI_LIST_INST or LIST_REEL for NL analysis & convergence issues

There is in the convergence window a ''tick'' that says ARRET = OUI if you select it even if the algorithm doesn't converge it will continue and finish the calculation, but the results may vary considerably and be erroneous.

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#5 2019-03-05 09:36:57

GPSalachs
Member
Registered: 2018-03-10
Posts: 177

Re: DEFI_LIST_INST or LIST_REEL for NL analysis & convergence issues

Regarding the DEFI_LIST_INST command, if i have an ECHEC criteria checked and an adaptation criteria checked, which one comes first?
In the event of a time step cut that fails, does the calculation continue with the adaptation criteria?

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