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#1 2019-06-27 10:32:12

pironman
Member
Registered: 2018-05-15
Posts: 50

usage of discret K_TR_D_N

I have to link a 3D component and I want to lock all the degree of freedom, except of rotation in OZ axis.
To do that, I create a 0D element, assign discrete element K_TR_D_N with very big stiffness on kx, ky, kz, kox, koy and zero stiffness around OZ axis.
Then, I use LIAISON_SOLID between this discret element and a surface of interest of the 3D element, and I fix the discrete element with DDL_IMPO = ENCASTRE.
With this method didn't work, but work if I set DDL_IMPO = 0 on DX, DY, DZ, DRX, DRY and nothing in DRZ.
My question is, why? If I set a zero stiffness around OZ axis, the rotation must be allowed also if I fix this degree of freedom with DDL_IMPO, why not?

Thanks

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#2 2019-06-27 13:19:51

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,569

Re: usage of discret K_TR_D_N

hello

when doing this sort of things
i set the fixed point wit a K_TR_D_N with a large stiffness on ALL six components
and relax the adequate DDL_IMPO
i set a  LIAISON_SOLID between the point and a surface

jean pierre aubry

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#3 2019-07-12 14:42:31

pironman
Member
Registered: 2018-05-15
Posts: 50

Re: usage of discret K_TR_D_N

thank you for your reply.
Another question: If I want a certain stiffness? I must use a K_TR_D_L?
what's the utility of K_TR_D_N?

Thanks

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