*static, riks 1

[mambo5]

Hi, i have my input file as the follwong,

*STEP, AMPLITUDE=RAMP, NAME=MIN 5, INC=500, NLGEOM=YES
*STATIC, RIKS
0.01, 1, 0.00001, 1
*Temperature
SLABNODES, 200
*END STEP
**
*STEP, AMPLITUDE=RAMP, NAME=MIN 10, INC=500, NLGEOM=YES
*STATIC, RIKS
0.01, 1, 0.00001, 1
*Temperature
SLABNODES, 400
END STEP
**
*STEP, AMPLITUDE=RAMP, NAME=MIN 10, INC=500, NLGEOM=YES
*STATIC, RIKS
0.01, 1, 0.00001, 1
*Temperature
SLABNODES, 600
END STEP

when i run the file, Abaqus said the *RIKS must be use in the last step. if i have addition step, i should use *restart in the next step, wondering how can i do that? where shoul i put the *restart? is it before *STATIC, RIKS, or before *STEP,...? what should i put after *restart to tell Abaqus that i want the analysis continue from the previous step? i.e *RESTART, READ/WRITE/STEP...?

please advise.

 

[bassmanjax]

You can only have one Riks step in an input deck, and it must always be the last step.

If you want to do a bunch of Riks steps in succession, then you will have to run them as individual analyses and use *IMPORT to read the results of the previous analysis.

Look up ABAQUS/Standard to ABAQUS/Standard results transfer in the docs.

Regards

Martin Stokes CEng MIMechE

 

[barney75]

Hi mambo5,
the message given by Abaqus mans that u cannot run an input file analysis with two Riks step, moreover the only one Riks step have to be the last one. To continue the analysis with another Riks step (that's your problem) this is my advise:
1) make a copy of your input file (i.e. let's call the 1st analysis file1.inp)
2) call the copied file file1_res.inp
3) In file1_res.inp file delete everything is above the last step (i.e. Riks step) unless u have defined parameter values. In this way this file will have only one step.
4) Change this step with the second riks step u want to perform.
5) Just above the keyword step insert this line:
*RESTART, READ, STEP=x1, INC=x2, END STEP
where:
- x1 is step of the file1.inp analysis u want restart from (in your case is the first Riks step u post in this thread)
- x2 is the increment (in your case I guess is the last one)
- see the documentation for the other options of this command
6) from abaqus command window run the input file analysis file1_res giving as restart file file1.inp

The same may be applied for the third Riks step saving a second file named file2_res

Easier to do than to say.....I hope this may help u

Bye

 

[mambo5]

BARNEY,

i not understand this,

5) Just above the keyword step insert this line:
*RESTART, READ, STEP=x1, INC=x2, END STEP
where:
- x1 is step of the file1.inp analysis u want restart from (in your case is the first Riks step u post in this thread)
- x2 is the increment (in your case I guess is the last one)

does it mean, if i doing my 2nd case, x1=MIN 5 and x2=500 ( AS REFER TO MY INPUT FILE ABOVE).

6) from abaqus command window run the input file analysis file1_res giving as restart file file1.inp
I DON'T UNDERSTAND 'giving as restart file file1.inp
', how could i do that?

please advise, many thanks.

 

[bassmanjax]

Best way to do this is to;

1 - Run the first Riks step on it's own. Remember to ask for a restart file at the end of this step (*RESTART, WRITE).
2 - Use *IMPORT to import the results into an input deck that contains the second Riks step. Run this deck and as before, write a restart at the end of the step.
3 - Use *IMPORT to import the results into an input deck that contains the third Riks step.

Also, have a look at section 9.2.1 of the Analysis Users Manual - this describes how to transfer results between analyses.

Regards

Martin Stokes CEng MIMechE