contact problem between 2 semi-disks

[Cervino86]

Good morning to all,
I have a problem with ansys because modeling 2 bound semi-disks, when I start the solution does not converge, leaving the following error message:

"the value uy at node xxxx is xxxxx it is greater than the limit..."

Now I ask you where you think I'm wrong.

This is a flat geometry in which the model is made with 2 contact semi-disks, I have bound the one in the bottom with recesses, while I have given a linear pressure to the above semi-discus, binding it in x direction.

Thank you for your concern

 

[volaff]

Step 1: Maybe you should have introduced yourself first.
Step 2: Find the offended node to display, I think it is a problem of knots with the same position but not coincident.

 

[Cervino86]

Hi.
I thank you for the answer, but the incriminated node is placed along a line that I have bound to the horizontal movements and on the same line I applied a linear pressure..... so it seems strange to tell me that undergoes such high movements I just do not understand.

 

[volaff]

Hi.
I thank you for the answer, but the incriminated node is placed along a line that I have bound to the horizontal movements and on the same line I applied a linear pressure..... so it seems strange to tell me that undergoes such high movements I just do not understand.

then attach the txt of the log file. and we see

 

[Cervino86]

ok I can't tie it, I put it as code, just run it:

! ------------------------- generazione modello test composto da rullo cilindrico di raggio r poggiante fra 2 piastre ------


/filname, modello_test
/title, test
/prep7

antype,static


!elementi finiti utilizzati

et,1,plane183 ! 2-d solid elements - 8 nodi + midside

keyopt,1,3,2

mp, ex, 1, 2e2
mp, prxy, 1, 0.3
mp, dense, 1, 7.85e-06

!------------------------------------------- geometry ------------------------------------------------------------------------------------------


!******************************** defining grandezze costanti da utilitzare nella geometria********************************************************

r=8
b=2*r
h=2
a=2 !metà lunghezza di contatto - fornire a valore in mm
alpha=asin(a/r)*180/3.14
p=2*a
l=1
r_1=a/sin(90-asin(a/r))))


****************************************************************************************************************************************


!definizione keypoints
csys,0

k , 1 , 0 , 0
k , 2 , r , 0
k , 3 , 2*r , 0
local,11,1,r,0
csys,11
k , 4 , r , 90+alpha
k , 6 , r , 90-alpha
k , 7 , r , 90

local,12,1,r,r
csys,12
k , 5 , r_1 , 270


csys,0

k , 8 , 0 , 2*r
k , 9 , r , 2*r
k , 10 , 2*r , 2*r
local,13,1,r,2*r
csys,13
k , 11 , r , 270-alpha
k , 13 , r , 270+alpha
k , 14 , r , 270

csys,12
k , 12 , r_1 , 90


!! ---------------- linee -------------
csys,0
l,1,2 !1
l,2,3 !2
larc,1,4,2,r !3
larc,4,7,2,r !4
larc,7,6,2,r !5
larc,6,3,2,r !6
larc,4,5,7,r_1 !7
larc,5,6,7,r_1 !8
l,2.5 !9
l,5,7 !10



l,8,9 !11
l,9,10 !12
larc,8,11,9,r !13
larc,11,14,9,r !14
larc,14,13,9,r !15
larc,13,10,9,r !16
larc,11,12,14,r_1 !17
larc,12,13,14,r_1 !18
l,9,12 !19
l,12,14 !20



!!! ---------------- aree -------------

al,1,3,7,9 !1
al,9,8,6,2 !2
al,11,19,17,13 !3
al,12,16,18,19 !4
al,4,10,7 !5
al,8,5,10 !6
al,14,20,17 !7
al,20,15,18 !8

dim=r/100

-------------------------------------------------------------------------------------------------------------------------------------------------
Type,1
mshape,1,2d
mshkey,0
esize,dim

amesh,5,8,1

! -------- parti senza contatto

Type,1
mshape,1,2d
mshkey,0
esize,r/25

amesh,1,4,1

Mcheck


!********


et,3,targe169, ! 2-d target elements
et,4,conta175, ! 2-d contact elements


mp,mu,1.0

keyopt,4,2,0
keyopt,4,3,0
keyopt,4,4,0
keyopt,4,5,0
keyopt,4,7,0
keyopt,4,8,0
keyopt,4,9,0
keyopt,4,10,2
keyopt,4,11,0
keyopt,4,12,0 !tipo di contatto


r,3,,1.0,0.1,0, !1-2-3-4-5-6
rmore,1.0e20,0.0,1.0, !7-8-9-10-11-12
rmore,0.0,0,1.0,1.0,0.5 !13-14-15-16-17-18
rmore,0,1.0,1.0,0.0,1.0 !19-20-21-23-24
rmore,10.0 !25

lsel,s,line,4,5,1
nsll,s,1
cm, card,node

Allsel

lsel,s,line,,14,15,1
nsll,s,1
cm,contact,node


! generate the target surface
nsel,s,,target
sln,s,0
Type,3
real,3
esurf


! generate the contact surface
nsel,s,,contact
sln,s,0
type,4
real,3
esurf

Allsel

************************


lsel,all
dl,1, ,all,0
dl,2, ,all,0

dl,11, ,ux,0
dl,12, ,ux,0


sfl,11,pres,0.625,
sfl,12,pres,0.625,

nsel,all
/sol
/status,solu
solve
finish
/post1
!*
/dscale,all,1.0
plesol, s,eqv, 1.0
/zoom,1,rect,0.0951753,0.110444 ,0.57751807811 ,-0.0606666639116

Thank you very much

 

[volaff]

Then, let's try like this.
take the number of the node that gives you the problem and mark its coordinates (the problem will be slow so you only have x and y ).

for example nodo1=(x1,y1).
Then do it like this:

nsel,all

nsel,s,loc,x1-0.01,x1+0.01
nsel,r,loc,y1-0.01,y2+0.01

No.

see how many knots have those characteristics and if there are two knots that have the same coordinates.

 

[Cervino86]

the knot is unique also in that around, and it is always the summit (top right) that I said before:frown:

 

[volaff]

azz beautiful story then.

 

[Cervino86]

Yeah... thank you anyway! :finger:

 

[Cervino86]

If anyone can interest me, I solved it. load-steps must be increased!