Modeling of single-lap bolt-joint (urgent)

[ndh]

Hi all,

I am a new user of ABAQUS. Now, I am using version 6.8 (CAE) to model a single-lap bolt-joint (see the attached files: 1-bolt.cae, job-1.inp, job-1.dat and job-1.msg). When I run the model, I get the following message "the system matrix has 2 negative eigenvalues". It seems that the reason for the warning message relates to the instability. I try to reduce the increment time but the problem still persists. It would appreciate if someone can help me to solve this.

Thank you very much.

NDH

 

[rstupplebeen]

You posted the *.DAT only. It states:
" WITH 1 ERROR MESSAGES ON THE MSG FILE
AND 130 WARNING MESSAGES ON THE MSG FILE"

My guess is that the 2 parts are disconnected and there is a rigid body motion. Be sure to constrain all 6 DOFs and to have connectivity between the models through coupling or contact. I hope this helps.

Rob Stupplebeen