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[CEROCCHI.1754896]

Hi everybody, i'm struggling with the use of link 180 in ansys mapdl.

I'm trying to reproduce a sailboat rig, and i need to model some stanless cables, used to sustain the mast. I thought that link 180 only tensile would be the perfect. In some load case the cable on one side of the boat are sagging, meaning they cannot hold any compression. I'm not interest in the deformed shape of the sagging cable of course.

  I triend some simply model to check the behaviour of the link 180 element used as a cable to sustain a beam, but it seems that even using seccontrol,,1 (only tensile) the result show a compression in the link elements. Why is the element not working with only tensile behaviour? any idea on how can i model the problem?

any help would be really appreciate. Thank you 

 

Here is  simpre problem whit a beam and 3 links that i used to check the behaviour:

 

FINISH

/CLEAR

 

/PREP7 !entra nel preprocessore

 

!element type

ET,1,BEAM188 !definisce elemento trave

ET,2,LINK180 !definisce elemento asta

 

!material property

MP, EX, 1, 69000000000  ! Modulo di elasticita MPa per il materiale 1 lega 6005a

MP, PRXY, 1, 0.3     ! Coefficiente di Poisson per il materiale 1

MP, DENS, 1, 2700 ! Densità lega 6005a

 

!sections

SECTYPE, 1, BEAM, CTUBE !definisce sezione albero circolare di prova

SECOFFSET, CENT

SECDATA, 0.048, 0.05

 

SECTYPE,2,LINK,2

SECDATA,0.0001,

SECCONTROL,1,1

 

!geometry

K,1,0,0,0

K,2,10,0,0

K,3,0,3,0

K,4,0,-3,0

K,5,0,0,3

 

L,1,2

L,2,3

L,2,4

L,2,5

 

!mesh

LSEL,S,LENGHT,,9.99,10.01 !SELEZIONA  TUTTE LE LINEE DI LUNGHEZZA COMPRESA TRA 9.99 E 10.01

LATT,1,,1,,,,1                                  

LESIZE,ALL,0.5

LMESH,ALL

ALLSEL

 

 

LSEL,S,LENGHT,,10.43,10.45 !SELEZIONA  TUTTE LE LINEE DI LUNGHEZZA COMPRESA TRA 9.99 E 10.01

LATT,1,,2,,,,2                                  

LESIZE,ALL,,,1

LMESH,ALL

ALLSEL

 

!carichi

!vincoli incastro 

DK,1,,,,0,ALL

DK,3,,,,0,ALL

DK,4,,,,0,ALL

DK,5,,,,0,ALL

!forza applicata su k2

FK,2,FY,-1000000

 

/ESHAPE,1,0        !mostra sezione elementi

/REPLOT

 

/SOL

/STATUS,SOLU

SOLVE

 

/POST1

/DSCALE,ALL,1 ! Use true scale (scale displacements by 1.0)

SET,LAST! read the last data set

PLNSOL,S,EQV,0,1.0 ! Plot equivalent (von Mises) stess

/ESHAPE,1,0        !mostra sezione elementi

/REPLOT

[Erik Kostson]

 

 

 

Hi

First use SECCONTROL,,1

Then

See the doc./help manual on LINK180.

(Nonlinear iterative solution is needed for tension or comp. only – so use in /SOLU , NLGEOM,ON, and NSUBST etc.).

https://innovationspace.ansys.com/forum/forums/topic/problem-with-the-link180-element/

 

All the best

Erik