Deciphering Output time

1

During a Calculix analysis, the command-line will report something like this:

increment 6 attempt 1
increment size= 1.171875e-02
sum of previous increments=7.031250e-02
actual step time=8.203125e-02
actual total time=8.203125e-02

why is the total time 8.2e-2 equal to the step time 8.2e-2?

in my step in PrePoMax I have:
Max increments: 10
Time period: 1 s
initial time increment: 1s (I use the default settings)
Min time increment: 1E-05s
Max Time increment: 1E30s

Also does s mean seconds? how would it even know how many seconds? in my analysis, the model is simply a cylindrical face on a long aluminum part sliding on a flat face at an incline. I move the cylindrical part by 1mm and was hoping to get reasonable stress values by going to a plastic material model. The elastic model ran fine. Switched to plastic and its just taking a very long time.

I have a sliding contact which I assume is doing OK or do you guys think its bouncing? I used hard contact for surface interaction. You can see in the summary that the # of contact elements starts large, then bounces a bit to small, then settles into some small value with a few more jumps. I figure the contact slave component is passing through edges on the master side?

SUMMARY OF C0NVERGENCE INFORMATION
STEP INC ATT ITER CONT. RESID. CORR. RESID. CORR.
EL. FORCE DISP FLUX TEMP.
(#) (%) (%) (%) (%)
1 1 1 1 50568 0.0000E+00 0.1000E+03 0.0000E+00 0.0000E+00
1 1 1 2 58826 0.8659E+05 0.8746E+02 0.0000E+00 0.0000E+00
1 1 1 3 37365 0.7734E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 1 4 29607 0.3123E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 2 1 50568 0.0000E+00 0.1000E+03 0.0000E+00 0.0000E+00
1 1 2 2 62018 0.8834E+05 0.9269E+02 0.0000E+00 0.0000E+00
1 1 2 3 22126 0.4754E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 2 4 22359 0.7030E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 3 1 50568 0.0000E+00 0.1000E+03 0.0000E+00 0.0000E+00
1 1 3 2 46029 0.5140E+05 0.5090E+02 0.0000E+00 0.0000E+00
1 1 3 3 12061 0.4937E+05 0.8021E+02 0.0000E+00 0.0000E+00
1 1 3 4 8350 0.4189E+05 0.6889E+02 0.0000E+00 0.0000E+00
1 1 3 5 7299 0.1519E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 3 6 6363 0.1132E+07 0.4729E+02 0.0000E+00 0.0000E+00
1 1 3 7 5337 0.7531E+06 0.5435E+02 0.0000E+00 0.0000E+00
1 1 3 8 4788 0.2095E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 3 9 4965 0.6452E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 3 10 6902 0.5382E+07 0.1000E+03 0.0000E+00 0.0000E+00
1 1 4 1 50568 0.0000E+00 0.1000E+03 0.0000E+00 0.0000E+00
1 1 4 2 28480 0.3557E+04 0.3400E+02 0.0000E+00 0.0000E+00
1 1 4 3 3243 0.2148E+05 0.4115E+02 0.0000E+00 0.0000E+00
1 1 4 4 1692 0.6610E+03 0.1882E+02 0.0000E+00 0.0000E+00
1 1 4 5 947 0.1920E+03 0.1034E+02 0.0000E+00 0.0000E+00
1 1 4 6 596 0.2002E+02 0.3475E+01 0.0000E+00 0.0000E+00
1 1 4 7 533 0.1199E+00 0.2821E+00 0.0000E+00 0.0000E+00
1 1 4 8 532 0.0000E+00 0.4097E-05 0.0000E+00 0.0000E+00
1 1 4 9 532 0.0000E+00 0.4810E-11 0.0000E+00 0.0000E+00
1 1 4 10 532 0.4377E+05 0.1436E+02 0.0000E+00 0.0000E+00
1 1 4 11 283 0.3706E+05 0.1397E+02 0.0000E+00 0.0000E+00
1 1 4 12 181 0.3779E+05 0.1059E+02 0.0000E+00 0.0000E+00
the value settles out
1 1 4 58 68 0.4487E+05 0.3696E+02 0.0000E+00 0.0000E+00
1 1 4 59 69 0.3787E+05 0.5726E+02 0.0000E+00 0.0000E+00
1 1 4 60 68 0.4484E+05 0.3698E+02 0.0000E+00 0.0000E+00
number of contacts jumps several times like this:
1 1 5 1 50568 0.0000E+00 0.1000E+03 0.0000E+00 0.0000E+00
1 1 5 2 24423 0.4984E+03 0.2349E+02 0.0000E+00 0.0000E+00
1 1 5 3 1244 0.1667E+04 0.3844E+02 0.0000E+00 0.0000E+00
slowly settles down
1 1 5 12 81 0.3507E+05 0.8755E+01 0.0000E+00 0.0000E+00
stable for a while
1 1 5 27 61 0.7924E+05 0.6412E+02 0.0000E+00 0.0000E+00
1 1 5 28 60 0.7887E+05 0.9274E+02 0.0000E+00 0.0000E+00

continues like that for a while

2

Here is a better look at the monitor

Screenshot 2021-07-16 162053
Screenshot 2021-07-16 1620531882×1548 256 KB

3

Are you running a dynamic or a quasi-static analysis?

4

this was a dynamic run. In PrePoMax, steady state was set to off.

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5

Hi, just a quick note regarding the output time:

It’s correct that step time = total time in your case.
In Calculix, a Step is defined in your .inp-file. Within a step, you apply loads and define contraints.

 *STEP
...
...
*END STEP

In your case, you only use one *STEP card. It is however possible to define multiple *STEP sections, e.g. for cases where you want to change the boundary conditions after some time. In that case, the step time always restarts at 0 at the beginning of the step. The total time is the sum of the time over all steps!

Hope this helps :slightly_smiling_face:

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