out-of-range velocities

[nanemo]

Dear all,

I'm simulating an impact test using ansys/ls-dyna, when I change an imput data "out-of-range velocities" error appears: for example,since I tried to insert the following soil and gravity datas


N,300000 ,8000,0,50,,,,
N, 300001,8000,0,7000,,,,
N,300002 ,-17000,0,7000,,,,
N,300003 ,-17000,0,50,,,,

EDMP,RIGI,5,7,7
MP,DENS,5,1.57e-7
MP,EX,5,200e3
MP,NUXY,5,0.33




TYPE, 2
MAT, 5
REAL, 1
ESYS, 0
SECNUM,
!*
FLST,2,4,1
FITEM,2,300001
FITEM,2,300000
FITEM,2,300003
FITEM,2,300002
E,P51X


ESEL,S, , , 12248
NSLE,S
CM,suolo,NODE
NPLOT
ALLSEL,ALL

ASEL,S, , , 1
NSLA,S,1
CM,surfsoil,NODE
NPLOT
ALLSEL,ALL



*DIM,TIME,ARRAY,2,1,1, , ,
!*
*SET,TIME(2,1,1) , 1
*DIM,gravity,ARRAY,2,1,1, , ,
!*
*SET,gravity(1,1,1) , -8820000
*SET,gravity(2,1,1) , -8820000
!gravity

EDLOAD,ADD,RBFY,0,8,TIME,gravity, 0, , , , ,


!contact


EDCGEN,STS,surfsoil,soil,0,0,0,0,0, , , , ,0,10000000,0,0



my model goes in instability:


"node # ... has out-of-range velocities"



Is there a certain reason why instability appears?

I tried to semplify my model, but I obtained no results

Is there literature about this problem? Is it contained in ansys help?


Oh I forgot... if possible, I'd like to maintain initial velocity for impacting body (20-30 Km/h) , target body thickness and mat prop (steel, 5mm)


tnx to all for attention, regards

 

[nanemo]

Can it be a coarse mesh problem?