#1 2022-07-24 15:08:41

EnKiNekiDela

Member

From: Slovenija

Registered: 2021-11-07

Posts: 24

[SOLVED] DYNA_NON_LINE Damping/dissipation

Greetings dear colleagues,

as I learn nonlinear analysis, having model combined with contact elements and large translations/rotations due to seismic motion, response increase (e.g. acceleration increase and spikes) became into play.

As of available documentation following damping/dissipation approaches are possible:
1. Material (behavior) dissipation
2. Dissipation in links, joints and assemblies (friction)
3. Modal damping (values from experiments)
4. Rayleigh damping (often fitted on modal damping values)
5. HF damping from the time scheme (if needed)

Due to contact elements, I am stuck with, it seems to me modal (3.) and Rayleigh damping (4.,  I am not completely sure of that) are off limits.
Dissipation with friction (2.) is present but limited on specific elements in structure.
So high response is still present at other sub-parts of structure as I have ELAS material.

So I intend to implement 1., 3. and 5.

Do yo have any experience on that matter like examples or existing CA documentation?
I am particularly interested in use of existing/verified non-linear materials: concrete and structural steel, since those are relevant for superstructure response and not for research of material non-linearity.
And what is your experience on calculation time using specific approaches?

Thank you so much and best regards.

Last edited by EnKiNekiDela (2022-09-08 18:55:28)

miib

Member

From: Near Goethe's Palm (Patavium).

Registered: 2021-03-23

Posts: 303

Re: [SOLVED] DYNA_NON_LINE Damping/dissipation

i done something with Rayleight damping
code-aster.org/UPLOAD/DOC/Formations/03-damping.pdf

little experience with beats
U4.52.02
code-aster.org/V2/doc/v13/en/man_u/u4/u4.52.02.pdf

U4.53.03
code-aster.org/doc/default/en/man_u/u4/u4.53.03.pdf

NO EXPERIENCE
U2.06.11
code-aster.org/V2/doc/v13/en/man_u/u2/u2.06.11.pdf

U4.84.01
code-aster.org/doc/default/en/man_u/u4/u4.84.01.pdf

R4.05.01
code-aster.org/V2/doc/v12/en/man_r/r4/r4.05.01.pdf

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Ma NON era chiaro ??? per chiarezza te lo spiego : a Code_Aster mi sono sempre approcciato come suo Studente, e quello che ho mostrato nei mesi passati erano SOLO i miei progressi nello studio. I professori da cui imparare??? li ho scelti da me.

EnKiNekiDela

Member

From: Slovenija

Registered: 2021-11-07

Posts: 24

Re: [SOLVED] DYNA_NON_LINE Damping/dissipation

Shortest answer after quite some experimenting is to introduce  material wit damping properties wisely and experiment with solver properties and precision of residuals at iterations....if model allows that.