Hi there,

I am trying to use VUInter in Abaqus/Explicit 2D axisymmetric model, but always encounter error：“The ratio of deformation speed to wave speed exceeds 1.0000 in at least one element.”

After testing using a simple 2D axisymmetric simulation, which consists of:

1. two blocks forming contact pair;
2. a most simple  VUInter describing contact stress sc=-k*g when g<0, and sc=0, otherwise.

 Strangely, even though the testing simulation didn't take any action and just let the system to relax (it should have g>0 and sc=0), elements on the edge were still deformed a lot and cause the error.

 At the right edge, the distortion disappares if I let the bottom block (or the top block) become longer than the other block.

However, this can only eliminate distortion at the right edge, becasue there is the rotation axis at the left edge.

p.s. the inp file and for file can be downloaded at google drive:

========= additional info. ================

I used the codes below in the "do k=1, nSecNod" loop to print information of the leftmost nodes on slave surface :

C      Print additional information for debug
          if (coordSec(1,k) .lt. 1D-10 .and. (gamma0-0.15D3) .lt. 1D-10) then
              WRITE(6,*) '>>>UINTER Debug: timStep=', timStep,'nodeID=',jSecUid(k), 'k=',k,'nSecNod=',nSecNod,'nMainNod=',nMainNod
              WRITE(6,*) 'g=', g,'stress(1,k)=', stress(1,k), 'tra=', tra
          endif
C

The results are initial normal with gap g=0, but soon becomce strange with large minus g. Besides, some funny nodes are also printed. Even funnier is that these nodes were not located on the surface defined for contact pair.

This is part of the printed information:

 >>>UINTER Debug: timStep=  9.619840002696054E-012 nodeID=           1 k=
          1 nSlvNod=         101 nMstNod=         101
g=  0.000000000000000E+000 stress(1,k)=  0.000000000000000E+000 tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  9.619840002696054E-012 nodeID=           1 k=
          1 nSlvNod=         101 nMstNod=         101
g=  0.000000000000000E+000 stress(1,k)=  0.000000000000000E+000 tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  9.619840002696054E-012 nodeID=           1 k=
          1 nSlvNod=         101 nMstNod=         101
g=  0.000000000000000E+000 stress(1,k)=  0.000000000000000E+000 tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  9.619840002696054E-012 nodeID=       20302 k=
        101 nSlvNod=         101 nMstNod=         101
g= -5.000000074505806E-002 stress(1,k)=   4719839746.88550      tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  9.619840002696054E-012 nodeID=       20302 k=
        101 nSlvNod=         101 nMstNod=         101
g= -0.150000002235174      stress(1,k)=   14159519240.6565      tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  9.619840002696054E-012 nodeID=       20302 k=
        101 nSlvNod=         101 nMstNod=         101
g= -5.000000074505806E-002 stress(1,k)=   4719839746.88550      tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  1.131150566421194E-011 nodeID=           1 k=
          1 nSlvNod=         101 nMstNod=         101
g= -4.702299091588757E-004 stress(1,k)=   44388195.6470127      tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  1.131150566421194E-011 nodeID=           1 k=
          1 nSlvNod=         101 nMstNod=         101
g= -5.094046056337581E-002 stress(1,k)=   4808616138.17952      tra=
 4.500000213738531E-003
>>>UINTER Debug: timStep=  1.131150566421194E-011 nodeID=           1 k=
          1 nSlvNod=         101 nMstNod=         101
g= -4.702299091588757E-004 stress(1,k)=   44388195.6470127      tra=
 4.500000213738531E-003