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Problem with modeling a joint in ABAQUS

Problem with modeling a joint in ABAQUS

Problem with modeling a joint in ABAQUS

(OP)
Hi friends,

I've modeled a WPC composite joint that it made with screw for a static shear analysis. After more than one hour computational time the job became aborted with this error message;
*Time increment required is less than the minimum specified,*
And some other warning messages such as;
Element distortion and the system matrix has some negative eigenvalues,
My units are in "mm" and everything is based on it, I've  considered 4 boundary conditions that one of them is my load. The WPC and screw densities are 1.14 and 7.86, respectively. I also defined plasticity for WPC model but not for screw.
When I changed solution control and set time incrementation as a discontinuous analysis, after nearly 13 increments, more than 5 hours computational time and also with same error messages it wasn't converged. Although one more warning message was added, that it is;

"There is zero FORCE everywhere in the model based on the default criterion. please check the value of the average FORCE during the current iteration to verify that the FORCE is small enough to be treated as zero. if not, please use the solution controls to reset the criterion for zero FORCE."

My mesh for the WPC is structure (except around the hole) and for the screw is sweap and I think it's fine enough.
Would it be ok if I'll raise the time incrementation again, in order to achieve convergence?   
If it is required, I could attach my .cae file.
I would be so happy, if anyone can help me in this problem.
Thanks

RE: Problem with modeling a joint in ABAQUS

Posting your model and/or pictures would help assess your issues.  I am not clear about your geometry or your boundary conditions.  I hope I can help more.

Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/

RE: Problem with modeling a joint in ABAQUS

It's a 14Mb file and I don't want to register with rapidshare thanks. If you remove the mesh from the cae file and upload it via this site (engineering.com) then the file will be smaller and easier to download. The model can easily be remeshed and hence checked.  

Tara

RE: Problem with modeling a joint in ABAQUS

(OP)
Tara, I removed the mesh but the size didn't change anymore! It only became 13Mbs. I uploaded it in another site. If you'll wait for seconds, you can download it easily and freely.
Thanks in Advance!
 

Milad Mohamadzadeh
Wood Structural Engineer
 

RE: Problem with modeling a joint in ABAQUS

Initially there is nothing to constrain the bolt from flying off.  You need to apply one of the following: stabilization, initially hold the bolt until contact occurs, or weak springs.  All of these can be turned off once the contact occurs.  I hope this helps.

Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/

RE: Problem with modeling a joint in ABAQUS

(OP)
You mean I should add more steps for this purpose? How can I constrain screw? I thought defining interaction is enough for contact condition.

Milad Mohamadzadeh
Wood Structural Engineer
 

RE: Problem with modeling a joint in ABAQUS

There is a slight gap between the screw and the hole.  This allows an infinitely small force to displace the screw and infinite distance.  You need something to constrain the bolt for the initial part of the simulation to avoid this rigid body motion.  I hope this helps.

Rob Stupplebeen
https://sites.google.com/site/robertkstupplebeen/

RE: Problem with modeling a joint in ABAQUS

(OP)
Rob,
I applied your tip in the model. But, after run nothing was changed. same warnings and same error message I get. Did you check out material property or interaction condition? Any other advice will be appriciated.

Milad Mohamadzadeh
Wood Structural Engineer
 

RE: Problem with modeling a joint in ABAQUS

hello corus

i aske u to help me in my broblem if you can please

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