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#1 2019-02-15 14:26:00

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

convergence of Mazars Model

I am starting new thread especifically for convergence issues in Mazar Model.

For a very simple case using a cube a compressive displacement was applied using Mazar model as attached below. The model was run with Non-Linear analysis. It was observed that the model runs only upto specific stress value (as shown in attached spreadsheet) before failing to execute.

Can anybody suggest what should be done in such condition? I heard using pilotage method, but I could not figure out how to use it.

Also, please feel free recommend any other model on concrete material that converges well.

Other post on Mazar model is at code-aster.org/forum2/viewtopic.php?id=16284&p=2


Attachments:
mazar.zip, Size: 47.52 KiB, Downloads: 84

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#2 2019-02-19 16:19:53

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

Re: convergence of Mazars Model

If you see the examples with cubes a little better the boundary conditions are pretty important, at least that is what i understood and made my study converge. My problem is when i begin meshing the study to more elements, there i begin having serious convergence problems.
Have you done any tries that converge with high density meshed elements in 3D with the Mazars model?Is there a correct way to approach this?

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#3 2019-02-20 12:32:22

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

Re: convergence of Mazars Model

I found a  workaround by letting the calculation run even when the convergence is not reached. In this way, the calculation reaches upto the peak strength of concrete but not beyond. Since concrete is considered to be crushed after the peak, this should be alright in my opinion.

  CONVERGENCE=_F(
    ARRET='NON', 
    ITER_GLOB_MAXI=500, 
    RESI_GLOB_RELA=0.0001
  )

Regarding the mesh size, I applied the approach mentioned above for a 3D RC beam (0.9*0.15*0.20 m) with 6mm rebars. So I assume the mesh was pretty small and succeeded to get the solution (matching with experimental result).

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#4 2019-02-22 14:48:00

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

Re: convergence of Mazars Model

Hello,

have you been able to utilize the SIGM_LIM and EPSI_LIM parameters of the mazars model? Is there any particular procedure one has to use?

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#5 2019-02-23 02:35:26

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

Re: convergence of Mazars Model

I asked the same question for a steel section at [code-aster.org/forum2/viewtopic.php?id=24001]. But did not get satisfactory answer.

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#6 2019-02-23 07:02:45

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

Re: convergence of Mazars Model

it is strange that the calculation won't stop when the parameters are met. might be better if you can go with PILOTAGE will try it and repost an answer.

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#7 2019-02-23 10:51:40

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

Re: convergence of Mazars Model

I am not familiar with PILOTAGE method. Can you please share a file that uses this method?

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#8 2019-02-26 15:17:09

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

Re: convergence of Mazars Model

I took some ideas from this post : .code-aster.org/forum2/viewtopic.php?id=20005
It uses a DEFORMATION approach with the PILOTAGE command.

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