Contact 178

[Sjoonus]

Hello,

I'm trying to model a portal structure using contact178 elements to stand on the ground. The most important modeling code is listed below:

ET,7,CONTA178 !3D node-to-node contact element met friction

!CONTA178 properties
KEYOPT,7,3,4 !Use weak spring that acts across an open contact or free sliding plane (contributes to stiffness and force)
KEYOPT,7,12,1 !Monitor and print contact status, contact stiffness
KEYOPT,7,5,6 !Z - component of defined element coordinate system (ESYS)

R,7,200000,0.5,1, ! FKN = 200000, GAP = 0.5 and START is initially open

! create model (using nodes)
!(...)
n,54,0,(b_wielstellen/2),0 !Wheel nodes
n,55,0,-(b_wielstellen/2),0
n,56,r_span,(b_wielstellen/2),0
n,57,r_span,-(b_wielstellen/2),0
n,80, 0,(b_wielstellen/2),-0.5 ! ground (rail) nodes
n,81,0,-(b_wielstellen/2),-0.5
n,82,r_span,(b_wielstellen/2),-0.5
n,83,r_span,-(b_wielstellen/2),-0.5


! make (frictional) contact elements between rail and wheels
TYPE,7 $REAL, 7 ! Type 7 = Conta178 contact element, REAL 7 = Fkn =200000

e,54,80
e,55,81
e,56,82
e,57,83

And then basically run the model with the following loadcases:

*dim,test,table,100,4 !create table
*tread,test,EQ_Duzce_Ansys_input,txt,, !import external data in that table


!general calculation settings
DELTIM,0.05,.01,1.1 !default timestep for each substep is 0.05

!write loadcases
*do,tel,1,100,1
!set time (read from previous defined matrix)
time,test(tel,1)

!loads in time
Acel,0,0,g
D,80,accx,%test(tel,2)*g%,,
D,80,accy,%test(tel,3)*g%,,
D,80,accz,%test(tel,4)*g%,,
D,81,accx,%test(tel,2)*g%,,
D,81,accy,%test(tel,3)*g%,,
D,81,accz,%test(tel,4)*g%,,
D,82,accx,%test(tel,2)*g%,,
D,82,accy,%test(tel,3)*g%,,
D,82,accz,%test(tel,4)*g%,,
D,83,accx,%test(tel,2)*g%,,
D,83,accy,%test(tel,3)*g%,,
D,83,accz,%test(tel,4)*g%,,


!control if matrix info only contains zero's (no loads defined) the calculation loop will then be stopped
*if,test(tel,1),eq,0,exit
!write loadstep file
lswrite,tel+1
*enddo !stop load case loop


!calculate all loadcases
lssolve,1,tel,1



But now the solution will not converge for the 2nd loadstep. What could be the problem? Can someone please help me!?
Thank you very much!