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LS-DYNA Simulation Template


Using the newly implemented feature of embedding FORTRAN type expressions in LS-DYNA using the *PARAMETER_EXPRESSION keyword, it is becoming easier to develop analysis templates that can provide flexible ways of changing analysis settings. A partial input file highlighting the possibilities is shown below, and the full file is available here: main.k. Using this as a template, one can import any model (prior to defining *CONTROL and *DATABASE keywords) and run the desired analysis. Parameter names used in the *PARAMETER_EXPRESSION card can be carefully chosen to reflect the names of the keywords in which they are used. LS-DYNA outputs the computed parameter values into the D3HSP file so they can be extracted and directly embedded for future runs if desired.

*KEYWORD
*PARAMETER_EXPRESSION
I ascfreq 1000000000
I binfreq 1000000000
I coarsen 2
I crspsid 913
I d3itctl 2
R tdybir 0
R tdybur stg2+(stg3-stg2)/10
R tdydth stg2
R term stg3
R tirep 0.248
...
*CONTROL_COARSEN
&coarsen,&crsang,0,&crspsid
*CONTROL_CONTACT
,&rwpnal
,,&rwgaps,1e20,&rwksf
*CONTROL_DYNAMIC_RELAXATION
,,,&stg3,,,,&idrflag
*CONTROL_HOURGLASS
&hg,0.05
*CONTROL_IMPLICIT_AUTO
&iauto,&iteopt,&itewin,&dtmin,&dtmaxc
*CONTROL_IMPLICIT_DYNAMICS
&imass,γ,β,&tdybir,&tdydth,&tdybur,&irate
*CONTROL_IMPLICIT_EIGENVALUE
&neigv
&isolid,&ibeam,&ishell,&itshell
*CONTROL_IMPLICIT_GENERAL
&imflag,&dt0
*CONTROL_IMPLICIT_SOLUTION
&nsolvr,&ilimit,&maxref
,,,1,0,&d3itctl
*CONTROL_TERMINATION
&term
*CONTROL_TIMESTEP
,,,,&dt2ms
*CONTROL_OUTPUT
1,3,,,,,,&iflush
*DATABASE_BINARY_D3DUMP
&dtdump
*DATABASE_BINARY_D3PLOT
&dtbin
*DATABASE_GLSTAT
&dtasc
*DATABASE_MATSUM
&dtasc
*DATABASE_NODOUT
&dtasc
...
*DEFINE_CURVE
10000,&drflag
0.0,0.0
&stg1,0.0
&stg2,1.0
&term,1.0
*LOAD_BODY_Z
10000,9810.0
*END

  • S. Ritt says:

    Hello!

    *PARAMETER_EXPRESSION is definitely a useful mean to study sensitivities and so on. Unfortunately, it does not work properly together with certain keywords. So far, I’ve the concern, that *PARAMETER and *DEFINE_COORDINATE_VECTOR and *MAT_LAMINATED_COMPOSITE_FABRIC does not fit together.

    Could you check that?

    Cheers, Stefan

    P.S.: I used v971 r3.1 SMP and DMP for checking, both windows and linux.

  • Suri Bala says:

    Hi Stefan,

    *PARAMETER keyword should be independent of other keywords. If you have a sample problem, you can send them to info at d3view dot com and I would be happy to look into.

    Suri

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