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**draf1992****Member**- Registered: 2018-04-17
- Posts: 7

Hello everyone,

I would like to learn how to model a hinge with a rotational spring. I know how to model a single hinge.

To get the hinge I used LIANSON_DDL.

LIAISON_DDL =_F ( NOEUD = ('V2', 'V3'),

DDL = ('DX', 'DX'),

COEF_MULT = (1., -1.),

COEF_IMPO = 0., )LIAISON_DDL =_F ( NOEUD = ('V2', 'V3'),

DDL = ('DY, 'DY'),

COEF_MULT = (1., -1.),

COEF_IMPO = 0., )LIAISON_DDL =_F ( NOEUD = ('V2', 'V3'),

DDL = ('DZ, 'DZ'),

COEF_MULT = (1., -1.),

COEF_IMPO = 0., )

Case 1 and 2 are in attached file. In the first case without rotational spring I received a Singular Matrix. In the second case without rotational spring I received correct results consistent with analytical calculations. I would like to avoid using discrete element SEG2. I tried with a discreet element of POI1. I added the zero 0D element to the V2 and V3 nodes. I'm not sure if this is a good solution.

Boundary conditions in the hinge wrote:

U=Y, QL=QP-F, ML=-k*(Up-Yp), MP=k*(Yp-Up).

U - displacement of the left beam

Y - displacement of the right beamUp - derivative of displacement of the left beam

Yp - derivative of displacement of the right beamk - spring stiffness

Ql - shear force in the left beam

QP - shear force in the left beamM - bending moment

How to add these additional conditions except that the displacements are to be equal for node V2 and V3. For any tips thanks in advance

Best

Rafał

*Last edited by draf1992 (2018-12-07 18:41:01)*

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**jlf****Member**- Registered: 2007-11-22
- Posts: 202

Hello,

You could try a DIS_TR (a K_TR_D_L on a SEG2 with a null size or not) with the same LIAISON_DDL for UX, UY, UZ.

You have 6 values to give for the K_TR_D_L :

- 3 values for displacement, with the LIAISON_DDL the values doesn't matter.

- 3 values for rotation, k

Watch out for the orientation of the SEG2, especially if its size is zero!

JLF

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