MAX. PENETRATION, MAX. CONTACT FORCE ERROR and NEGATIVE EIGENVALUES

[MarceloM]

Hello,

I'm doing a simulation in abaqus standard and i wont to know if MAX. PENETRATION, MAX. CONTACT FORCE ERROR and NEGATIVE EIGENVALUES is a problem or i can stay with them? If yes, how can i fix them and how they afect my results.

Some exemples:
"***WARNING: THE SYSTEM MATRIX HAS 23 NEGATIVE EIGENVALUES."

"MAX. PENETRATION ERROR 2.51836E-09 AT NODE SUPORTEPE-31-1.904 OF CONTACT
PAIR (ASSEMBLY_S_SURF-822,ASSEMBLY_M_SURF-849)
MAX. CONTACT FORCE ERROR -77.7828E-06 AT NODE SUPORTEPE-32-1.379 OF CONTACT
PAIR (ASSEMBLY_S_SURF-701,ASSEMBLY_M_SURF-704)
THE ESTIMATED CONTACT FORCE ERROR IS OUTSIDE OF CONVERGENCE TOLERANCES."

"MAX. PENETRATION ERROR 40.3043E-09 AT NODE SUPORTEPE-25-1.20 OF CONTACT
PAIR (ASSEMBLY_S_SURF-829,ASSEMBLY_M_SURF-828)
MAX. CONTACT FORCE ERROR 794.025E-06 AT NODE SUPORTEPE-23-1.10226 OF
CONTACT PAIR (ASSEMBLY_S_SURF-572,ASSEMBLY_M_SURF-842)
PENETRATION ERROR TOO LARGE COMPARED TO DISPLACEMENT INCREMENT."

Thank you.

 

[Mustaine3]

If the analysis find convergence in later iterations and the results look plausible, then you don't have to worry.

 

[MarceloM]

Okey, Thanks!