Learning Forum

[A2148]

Hello,

I'm simulating the creep analysis using a modified time hardening model. I have found all the material constants through ANSYS APDL curve fitting. Moreover, I am taking 2-time steps. In the first time step, I'm using 500 initial subsets and a minimum of 10. In the second time step, I'm using 1000 initial subsets with a minimum of 20.

Here, the problem is that the analysis is running only at the end of the 1st time step. It shows the error at the beginning of the 2nd time step with creep and large deflection effects on.

About contact, I'm using frictionless contact. Furthermore, I also tried newton raphson to review the unbalanced force. I have used the finner mesh to mitigate the unbalanced force but have not gotten results.

Anyone give me recommendations that will be appreciated...Thanks

[A2148]

Here are the further errors;
"the creep integration algorithm does not converge for element 11872,
material 1, creep model 6."

[peteroznewman]

Under Analysis Settings, for Current Step Number 2, set the Initial Substeps to 10000 and Minimum Substeps to 1000 and see if that helps.

[A2148]

Hi, thank you for the reply. I'll apply those conditions and check the results. if there will be any problem I'll get back to you sooner. Much appreciated

[Mike Rife]

You should be able to take the creep law used along with the stress, temperature, and time increment and hand calculate the expected creep strain (or strain rate for most creep laws). It's a good sanity check. Also remember that once fitted the creep law constants cannot change their unit system so make sure they are entered in WB Engineering Data in the same system of the data you used during the curve fit, and WB Mechanical is set to the same unit system. It's pretty easy to blow up a creep law term to some non-a-number with the wrong units (been there, done that plenty!).
Post process the non-converged results - that may tell you something as well.
Mike