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#1 2018-12-06 20:55:06

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

Hinge with rotational spring between two beam elements

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 beam

Up - derivative of displacement of the left beam
Yp - derivative of displacement of the right beam

k - spring stiffness

Ql - shear force in the left beam
QP - shear force in the left beam

M -  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)


Attachments:
Figure.pdf, Size: 3.62 KiB, Downloads: 7

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#2 Today 13:32:37

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

Re: Hinge with rotational spring between two beam elements

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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