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## #26 2020-10-12 10:04:49

Clement M
Member
Registered: 2020-10-08
Posts: 11

Ok thank you

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## #27 2020-10-12 12:26:25

mib
Member
Registered: 2019-11-10
Posts: 88

### Re: How to increase the speed

Hi

good news :

YES is possible to "concatenate" med file of stage 1 with med file of stage 2. imposeign how start coditions of stage 2 the final conditions of stage 1.

resnonla = DYNA_NON_LINE(CHAM_MATER=fieldmat,
COMPORTEMENT=_F(DEFORMATION='SIMO_MIEHE',
RELATION='VMIS_ISOT_LINE'),
CONVERGENCE=_F(ITER_GLOB_MAXI=30),
>>>>>>>>>> ETAT_INIT=_F(EVOL_NOLI=resnonl),<<<<<<<<<<<<<<<<<<<<<
EXCIT=_F(CHARGE=rotaa),
INCREMENT=_F(LIST_INST=timesa),
MODELE=model,
NEWTON=_F(MATRICE='TANGENTE',
PREDICTION='TANGENTE'),
>>>>>>>>>>RESULTAT=resnonl,<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
SCHEMA_TEMPS=_F(FORMULATION='DEPLACEMENT',
SCHEMA='HHT'),
SOLVEUR=_F(METHODE='MUMPS'))

here the video :

(for my videos i used small values of acceleration velocity and time range, for a rapid computation)

Last edited by mib (2020-10-12 12:32:25)

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## #28 2020-10-13 09:52:26

mib
Member
Registered: 2019-11-10
Posts: 88

### Re: How to increase the speed

Clement M wrote:

Yes it is basicly what I want to do.
To explain you a bit better I am in intership and my goal is to simulate the expansion of a flywheel. Some experiments with the same flywheel at different speed were made and my aim is to be as close as possible from this results. But before working with this complex object I am simulating a simple cylinder with an hole, so a pipe, in two dimension.
It seems to work fine but I can t do a lot of revolution at high speed (my goal is 20 000 rpm) because I have convergence problem. So I need to have an extremely small timestep and I have problem with memory.
So to solve this problem and to be closer from the experiments I am trying to have a speed which goes from 0 to 20 000 rpm in few seconds and not directly 20 000 rpm during the whole simulation. As I didn t have the speed in my rotation formula I was trying to change an other parameter. I try with dtheta but as it wasn t a scalar anymore it wasn t recognized in the formula and it didn t work. So I don t really know what to do. I hope you will understand better my problem.
What you send me seems way better but I don t understand why cos(t) and how to define n(dt) in code aster.
Thanks again for your help I really appreciate it.

Formula 1 or MotoGP flywheel ???? :-D

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## #29 2020-10-13 11:29:05

sameer21101970
Banned
Registered: 2019-09-06
Posts: 354

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## #30 2020-10-14 11:11:42

mib
Member
Registered: 2019-11-10
Posts: 88

### Re: How to increase the speed

Only for Italian User

Troll o è davvero Clemente ???

napoli.repubblica.it/dettaglio/tangenti-bufera-su-mastella-in-un-file-la-lista-di-raccomandati/1755990/2

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## #31 2020-10-17 10:11:07

Clement M
Member
Registered: 2020-10-08
Posts: 11

### Re: How to increase the speed

Hi,
Thanks for you time it is working fine. I can t share the flywheel mesh for confidentiality reason.
And I am not italien

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## #32 2020-10-29 11:02:51

Clement M
Member
Registered: 2020-10-08
Posts: 11

### Re: How to increase the speed

Hello again
I was wondering if it was possible to set a variable time step, for example proportional to 1/V for the ramp, and then a constant one. The goal would be to reduce the simulation time.
Thanks a lot if you answer me again and have a nice day

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