Skip to main content

Ansys Error what's going on ???

Submitted by allspot on

Dear All,

 

I have much problem when modelling my project with ANSYS, one of problem that I met always like this 

 *** ERROR ***                           CP =     296.828   TIME= 14:56:15

 A small negative equation solver pivot term has been encountered at the

 ROTZ degree of freedom of node 11758.  Check for an insufficiently     

 constrained model.

purpose of my project is to analysis stress distribution in welded tubular joint with MPC (combine between solid element "weld" and shell element "chord & brace")....

 Help me please ...... Really I need help

this is command that I put in ANSYS

/prep7

/units,si

----------    !weld

et,1,186

et,2,181

keyopt,2,3,2

et,3,170

keyopt,3,5,4

et,4,174

keyopt,4,4,2

keyopt,4,5,3

mp,ex,1,2.5E8

mp,prxy,1,.3

mp,dens,1,7850

r,1,0.01128

cylind,0.19172,0.203,-2.065,2.065,0,90

wprota,,-45

cylind,0.07556,0.07,0,2.2402,-90,90

csys,4

agen,2,3,,,,,0.015

vsba,2,13

vdele,4,,,1

vsba,1,15

vdele,2,,,1

vsba,3,20

vdele,1,,,1

cylind,0.0872,0.091,0,1,-90,90

vsba,4,7

vdele,5,,,1

vdele,1,,,1

vglue,2,3

l,24,27

l,21,28

al,2,3,41

al,1,4,39

al,4,36,44,3

va,4,7,8,9,23

vglue,1,2,4

----------    !brace

cylind,0.07,0.07278,0,2.2482,-90,90

vsba,1,18

vdele,2,,,1

vdele,4

adele,28,30,,1

adele,2,26,26-2,1

----------    !chord

wprota,,45

cylind,0.19172,0.19736,-2.065,2.065,-90,90

vsba,1,17

vsba,2,15

vdele,4

vdele,7,,,1

vdele,1

adele,3,31,31-3,1

adele,19,,,1

adele,24,28,2,1

adele,1,2,,1

adele,9,29,29-9,1

----------    !meshing setting

smrtsize,1

vsel,s,,,5,6

vatt,1,,1

vsweep,5

vsweep,6

vsel,s,,,3

vatt,1,,1

extopt,aclear,0

vsweep,3

aatt,1,1,2

mshkey,2

mshape,0,2d

lesize,30,,,20

lesize,8,,,20

lesize,15,,,40

amesh,27,30,3

amesh,4

----------    !MPC setting

type,3

real,2

asel,s,,,17,18

asel,a,,,15

nsla,s,1

esurf

type,4

real,2

lsel,s,,,25,29,4

lsel,a,,,51

nsll,s,1

esurf

----------    !load and pedestal setting

/solu

local,11,0,0,0,0,0,-45

f,4114,fz,2.5E+6

csys

lsel,s,,,8,10,2

dl,all,,ux

dl,all,,uy

dl,all,,uz

dl,all,,rotx

dl,all,,roty

dl,all,,rotz

alls

solve