Some problems with abaqus cae? 2

[tatika]

Hi

well the problem i am getting is that i am applying a moment on a W steel section, the problem is that when i am running the model, i get some messenges and the process is aborte. I have being appling the moments , putting a RP, then applyin a kinematic coupling and the applying the moment at the RF, i think part of the problem is that, so someone can suggest to me any other way how to apply a moment on a section?

 

[DanStro]

What are the errors you are getting? That probably will help get you in the right direction.

 

[tatika]

Hi Danstro

well i am getting a lot of problems, i am trying to do a model of a Heather plate connection but my supervisor asked me to start with two plates and bolts and applying a moment. i did the model of the heather plate connection but it wa snot working, thats why he suggested this.

When i am running the file it appears:

The model database "C:\Temp\modelo 5-1.cae" has been opened.
The job input file "Job-1.inp" has been submitted for analysis.
Job Job-1: Analysis Input File Processor completed successfully.
Error in job Job-1: Too many attempts made for this increment
Job Job-1: Abaqus/Standard aborted due to errors.
Error in job Job-1: Abaqus/Standard Analysis exited with an error - Please see the message file for possible error messages if the file exists.
Job Job-1 aborted due to errors.

and if i check on the messege box it says things like:

MPCS (EXTERNAL or INTERNAL, including those generated from rigid body definitions), KINEMATIC COUPLINGS, AND/OR EQUATIONS WILL ACTIVATE ADDITIONAL DEGREES OF FREEDOM

Output request esf1 is not available for element type c3d8r

Output request sf is not available for element type c3d8r

Output request esf1 is not available for element type c3d8r

Output request sf is not available for element type c3d8r

Output request esf1 is not available for element type c3d4

Output request sf is not available for element type c3d4

Output request esf1 is not available for element type c3d4

Output request sf is not available for element type c3d4

Output request vf is not available for this type of analysis

Boundary conditions are specified on inactive dof of 333 nodes. The nodes have been identified in node set WarnNodeBCInactiveDof.

The strain increment has exceeded fifty times the strain to cause first yield at 1 points

The system matrix has 5 negative eigenvalues.

The strain increment has exceeded fifty times the strain to cause first yield at 170 points

The system matrix has 22 negative eigenvalues.

The strain increment has exceeded fifty times the strain to cause first yield at 432 points

The strain increment is so large that the program will not attempt the plasticity calculation at 1 points

The system matrix has 2 negative eigenvalues.

The system matrix has 1 negative eigenvalues.

The strain increment has exceeded fifty times the strain to cause first yield at 3 points.



I know a lot of of things, i am really desperated because i am learning by my self and i need this in order to continue with my thesis.

i would apreciate if you can help and excuse me because of the long messege

i have attached a file, it is an easy one but no working


Tatika

 

[DanStro]

I'm also self-taught so I am no expert but I'll help where I can.

I don't know what it is supposed to look like but I was able to get the model to run by turning on "Automatic Stabilization" in Step 1. I kept the default values that come up from that.

HTH,
Dan

 

[mrgoldthorpe]

From the warning messages it looks like the load increments being used are too large and lead to excessive plastic deformation in some of the elements. A few things for you to consider:

* Check that you are not loading the stucture beyond its collapse load.

* ABAQUS will assume perfectly plastic (non-hardening) response when the equivalent plastic strain anywhere exceeds the largest plastic strain you input for that material.

* If you don't want the above to occur consider allowing further strain-hardening by entering another pair of stress/plastic strain values in the *PLASTIC properties.

* In the step that is failing restrict the maximum load increment size to say 5% of the step size. This will prevent ABAQUS increasing the load increments too much.

 

[mrgoldthorpe]

I've taken a quick look at your input file. You are applying a concentrated force at node set _PickedSet57 (node 1). I'm not sure where this is your model, but beware that local yielding will occur around that node because both "Bolts" and "Steel s355" materials have plastic properties. It is better to distribute the load.

You still need to consider the points I made above.

 

[tatika]

Hi guys

Thanks too much to you, but i got new problems, well now this is running but the way how i consider it should be working i think it is not properly.

I did two models, one applying just a puntual force and it looks it works perfect, but when i am applying a moment i consider it does not work in the sence that i consider the way how it works it should not be like that, i think the plate where the moment is applyed at the low part , it should be attached to the other plate and at the upper part, it should be moving away from the other plate,bu as you can see, both sides are moving the same, do you know how can i make it better?

i am trying by applying a couple (two puntual forces= to the moment and a certain distance) but it looks itis not working

i am attaching the files


Thanks a lot if you can help me

Tatika

 

[tatika]

This is the second file

 

[loki3000]

* If you don't want the above to occur consider allowing further strain-hardening by entering another pair of stress/plastic strain values in the *PLASTIC properties.


what happens if you set the failure stress (strain)?