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## #1 2019-02-15 16:18:42

chenghui62000
Member
From: Norway
Registered: 2018-06-19
Posts: 79

### How to define a displacement-depended forces in code_aster?

Hi everyone,

I am a PhD candidate at the University of Stavanger, Norway. Currently, I get stuck with Code_Aster. I have seen the training material and some tutorial videos, but I still cannot figure out a way to define a formulation to update the forces on the structure according to its displacement.

Thank you very much in advance.
Hui Cheng

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## #2 2019-02-15 20:13:16

chenghui62000
Member
From: Norway
Registered: 2018-06-19
Posts: 79

### Re: How to define a displacement-depended forces in code_aster?

What I am trying now:
(1) extract the coordinate of each node ( X, Y, and Z) at each timestep.
(2) calculate the orientation of each (cable) element in the global coordinate system by
cx= (X1-X2)/L,    cy= (Y1-Y2)/L,    cz= (Z1-Z2)/L.
L is the (cable) element length. X1, Y1, Z1 is the coordinate of the start of one (cable) element, X2, Y2, Z2 is the coordinate of the end of one (cable) element.
(3) calculate the updated force according to the orientation. The force is written as
Fx=A*cx, Fy=B*cy, Fz=C*cz. A, B, C are three constant number.
(4) assign the updated force onto the node at each timestep.

The problem is that I could not extract the coordinate of each node at each time step during the calculation. and I am not sure whether I could assign the updated force onto the node during the simulation.
BTW, I am trying to use the DYNA_NON_LINE solver.

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