Dear Sir,

I tryed to model the Beam with
external cables (EXTC), as it is
explained in the example manual,
but there are some errors and the
analysis can't be executed.

Also when I try to change the messing
to some macroelements, there is an
internal error.

I have already send to the cervenka@
an e-mail with my model and a pdf with
the error messages.

Thank you for your time.

Hello Everybody,

seeing your discussion about the CC5ParamYield F: project_stress_on_f_division by zero problem, I want to comment on the following. This error means the following:

- the stress is so far outside the failure criterion that it cannot compute the return direction to return to the failure/yield surface.

The cause of the error is usually due to:

- either wrong definition of material parameters, if you modified some parameters by hand manually then you should check
  if your compressive strength or tensile strength or the onset of the compression FC0 are meaningfull. If your parameters were
  generated by ATENA, this is not probably the reason.

- the next reason is the divergence of your problem. Due to divergence of the solution, the stresses are now so big that the program
  cannot find a solution. The reasons for divergence could be again many, but most common situations are:

    - wrong boundary conditions
    - wrong loading, load is for instance applied at a single point and not distributed by some loading plate. Please, understand
      that in reality there is nothing like a point load or support. Point load or support is a singularity and your stresses will
      go to infinity there if you make a sufficiently small mesh.
    - loading is applied by too large steps
    - loading is so high the structure cannot survive it. Then you should use and arc-length method or check the expected load
      level and reduce the load.

Well if you are not able to solve the problem, I suggest that you send us your input file, without the results and we can
check what is wrong.

Regards

Jan Cervenka

Well, I can only say the same as in a previous message in this thread (2010-09-02 11:04:43) - hard to guess without seeing the model.

In how many steps do you apply the swelling strain? 1 per mill = 1000 microstrain is already quite a lot - you may need more than 10 load steps for that. And, of course, double the number of steps when you apply two times more strain.

Sir,
I also face similar problem when this massage appear

CCMaterials Extended AExc:
CC5ParamYield F: project_stress_on_f_division by zero.

I model the 3D RC Square RC column and introduced the swelling at load case in the concrete to mimic the effect of expansion. I tried with value of swelling of 0.001 and 0.002 (strain), Atena can complete the analysis, beyond the value 0.002 Atena unable to complete the analysis.

Please help.

I am afraid it is not possible to determine the problem source without seeing the model. Please send it to our general support email (cervenka@...).

thank you
there is an another error generated, when I was interested for generating FE mesh int the beam.
an internal error has occured

ID: A3 MasterSlave.pas/13
Module: C/PROGRA~1/CERVEN~1/ATENAV4/A3Pre_1.dll

If I am continuing with out solving this error, then massage comes

(x) Internal error while preparing mesh generator input!
Group3 i.e. Steel plate which is attached to beam for loading, not generated.

The dicision where to stop of course depends on the type of problem and of the kind of results you are interested in.
Basically, if you are interested in the max. load and you see in the monitor L-D graph that the force/reaction has reached the peak and decreases, you can stop.

Please read the paragraph "I get the warning "Convergence criteria (within line search) not satisfied due to eta limit, continuing superordinate iteration" during analysis, what does it mean?" in the Known Issues page of our Web (Products » ATENA » Known problems)
http://www.cervenka.cz/products/atena/known-problems

Thank you
Actually after howmuch load step I have to stop! It is very difficult to juge from the result, as different beam requires different analysis step, Weather from the graph I have to predict that my beam is failed or is there any other criteria.

Is there any provision in ATENA that, it stop the work by providing massage.

Also, after each step. The massage come

(*) Warning convergence criteria not satisfied.

Is this warning effects the results.

Hard to say without seeing your model...

Somewhere in post-peak this can happen. It basically means there is very large damage in a material point. Are you really interested in results in that step and later, or is the structure already almost destroyed?

If this happens at an early stage, the reason is usually a too long loading step, or wrong boundary conditions. It also might be too high local damage (regionally restricted - far before global failure). In that case, we should be able to help you modify the material or solution parameters to prevent/reduce the numerical problems.