FEAP User Forum

FEAP => Input File Issues => Topic started by: Lukas_Poggenpohl on May 12, 2020, 06:12:11 AM

Title: LOAD PROP and PERIodic CAUChy
Post by: Lukas_Poggenpohl on May 12, 2020, 06:12:11 AM
Dear FEAP Forum,

I am currently trying to load an RVE with different deformations, sequentially. (E.g. first tension- then shear load as specified in the example attatched)

I am facing the problem, that the geometry is not loaded using PERIodic CAUChy. If I specify BCs via CDIS (Instead of PERIodic CAUChy), it works.

According to the O-File, load sets 1 and 2 are generated but the geometry is not loaded. (Warning for zero RHS.)

The example Input and Output files are attatched, I am using FEAP 8.4.

Thanks for the help and stay healthy,

Lukas Poggenpohl
Title: Re: LOAD PROP and PERIodic CAUChy
Post by: Prof. R.L. Taylor on May 12, 2020, 12:50:35 PM
You have ELINK before the END of mesh command.   Thus, no linking is performed.  THe ver8.4 is known to have problems with load groups so it may not work,  I am not sure you can load two periodic cauchy definitons, check which one is used -- probably the last one.
Title: Re: LOAD PROP and PERIodic CAUChy
Post by: Lukas_Poggenpohl on May 13, 2020, 03:26:03 AM
Dear Prof. Taylor,

the ELINk does work now. Thank you for the fast response.

As you expected, only the last CAUCHY is used (for both PROP commands). I now tried FEAP 8.5 which shows the same issue.

Is there a possibility, to circumvent/solve this problem?

Kind regards,

Lukas Poggenpohl
Title: Re: LOAD PROP and PERIodic CAUChy
Post by: Prof. R.L. Taylor on May 13, 2020, 10:22:38 AM
It could be done.  It would require tracking where the arrays are used, adding a loop around them for the number that are defined and accumulating the result.  I am not sure how many changes are required -- it is something we would possibly do in a future release as it involves changes in multiple modules. 

You can do by starting with the inputs which will be done in 'pmesh.f' in ./program directory and follow all the uses of the arrays.  I suppose it would be necessaary to limit to a few arrays as my memory is that none are allocated.
Title: Re: LOAD PROP and PERIodic CAUChy
Post by: Xuannamdo-danang on June 09, 2020, 09:13:06 AM
Dear Prof. Govindjee,

Thanks for your reply

I enclose 3 pictures showing nodes needed to be linked and an input file in which I used commands: LINK and PERIODIC. Could you please let me know whether I exactly followed your instructions?

Thank you so much

Sincerely yours,
Nam Do