Contact surface and pressure error

[Megatron01]

Hi

I am doing a finite element analysis of a rectangular hollow beam section of steel.....

I need to apply pressure on the top of the beam using stress block....and the beam will show deflection...moreover the block and the beam are meant to joint by contact elements.....

Now I have managed to do the contact part .... but i cant apply pressure over it, as it shows me rigid body motion error!!!!

I can also apply deformation ...but I think the contact / the model is not properly done .......

so plz ,, can anyone help me in this regard....

I am posting my code below....

Thanks : )______________________________________________________
finish
/clear

/title,Rectangular Hollow section

/prep7

a=4
b=2
c=.08
d=20
a1=5
a2=4
b1=1
b2=-2
t3=1

et,1,shell143
r,1,c,c,c,c
mp,ex,1,28000
mp,prxy,1,0.3

TB,MISO,1,1,10

TBPT,,1,28000
TBPT,,1.285714,36000
TBPT,,1.5,42000
TBPT,,1.7142857,48000
TBPT,,1.9285714,54000
TBPT,,2.142857,60000
TBPT,,2.375,66500
TBPT,,3,69000
TBPT,,4.5,73000
TBPT,,6,78500

et,2,shell143
r,2,c,c,c,c
mp,ex,2,28000
mp,prxy,2,0.3

TB,MISO,2,1,10
TBPT,,1,28000
TBPT,,1.285714,36000
TBPT,,1.5,42000
TBPT,,1.7142857,48000
TBPT,,1.9285714,54000
TBPT,,2.142857,60000
TBPT,,2.375,66500
TBPT,,3,69000
TBPT,,4.5,73000
TBPT,,6,78500

et,3,shell143
r,3,t3,t3,t3,t3
mp,ex,3,28000
mp,prxy,3,0.3

ET, 5, 170 ! Target
ET, 4, 174 ! Contact surface-to-surface
R, 4, , , 1, 0.1, 0,
KEYOPT, 4, 1, 0
KEYOPT, 4, 2, 0 ! Augmented Lagrange 0, Penalty Method 1
KEYOPT, 4, 4, 0
KEYOPT, 4, 5, 3 ! Close gap 1/ Reduces initial penetration 2/ Both 3
KEYOPT, 4, 7, 2 ! Automatic bisection of increment 1, maintain reasonable 2
KEYOPT, 4, 8, 0
KEYOPT, 4, 9, 0 ! Include 0 / Exclude initial penetration 1
KEYOPT, 4, 10, 2 ! Update contact stiffness at each iteration
KEYOPT, 4, 11, 0 ! Beam/Shell thickness effect 1

! defining nodes
k,1,0,0,0
k,2,b,0,0
k,3,b,a,0
k,4,0,a,0
k,5,0,0,d
k,6,b,0,d
k,7,b,a,d
k,8,0,a,d
!
!defining area
!
!

a,6,2,3,7
a,8,7,3,4
a,5,6,2,1
a,5,1,4,8

lsel,all
lesize,all,0.20

!
!Meshing
!
type,1
mat,1
real,1

asel,s,loc,x,(b/2),(b/2)
asel,u,loc,y,0,0
amesh,all

nsel,s,loc,x,0,a
nsel,r,loc,y,a,a
nsel,r,loc,z,0,b

CM, N_CONTA, NODE

type,2
mat,2
real,2

asel,all
asel,u,mat,,1
allsel,all
amesh,all

allsel,all
nummrg,node

! for the plate
!
k,9,a,a,0
k,10,a,a,b
k,11,b2,a,b
k,12,b2,a,0

a,9,10,11,12

type,3
mat,3

asel,all
asel,u,mat,,1
asel,u,mat,,2

lsel,s,loc,x,b2,a
lsel,r,loc,y,a,a
lsel,r,loc,z,0,b
lesize,all,0.20


allsel,all
amesh,all

asel,all
asel,u,mat,,1
asel,u,mat,,2

nsel,s,loc,x,b2,a
nsel,r,loc,y,a,a
nsel,r,loc,z,0,b

CM, N_TARGET, NODE

allsel,all
nummrg,node
! define contact nodes and elements

REAL, 4
NSEL, S, , , N_TARGET
TYPE, 4
ESLN, S, 0
ESURF

! Generate the contact surface

NSEL, S, , , N_CONTA
TYPE, 5
ESLN, S, 0
ESURF

finish
/solu
!
!pressure & Restraints
!
!
nsel,s,loc,x,0,0
nsel,r,loc,y,0,0
!d,all,uy,0

nsel,a,loc,x,2,2
nsel,r,loc,y,0,0
d,all,uy,0
d,all,ux,0

!pressure

asel,s,mat,,3 ! select top area
nsla,s,1

!d,all,uy,-1 !! Can I get the defletion
!! using deformation

sf,all,pres,5 ! It supposed to take pressure = 500

allsel,all
SOLVE !Solve the resulting system of equations

FINISH

___________________________________________________________

 

[Megatron01]

Plz , someone give me hint or any direction......