Learning Forum

[malte.koehn]

Hi everyone,

I’m relatively new to LS-DYNA and I’m facing a problem with the *CHANGE_CURVE_DEFINITION command.

In my initial input deck, I define a curve as follows:

*DEFINE_CURVE
$       ID      sidr       sfa       sfo      offa      offo    dattyp   unused1
         1         0       0.0       0.0       0.0       0.0         0         0
$#                a1                  o1
                 0.0                 0.0
$                 a1                  o1                                 unused1
                 2.0                0.05

Now I want to change this curve after a restart, but the *CHANGE_CURVE_DEFINITION command does not work as I expected.

I used it as follows:

*CHANGE_CURVE_DEFINITION
$       ID
         1
$#                a1                  o1
                 2.0                 0.5
$                 a1                  o1                                 unused1
                 4.0                 0.5

 

 

When I run the restart, I get the following error:

 *** Error 10246 (KEY+246)
     line contains improperly formatted data
      reading *CHANGE_CURVE card.
          At line# 9 of file
 d:\lsdyna\restart\inputbalken_r.k
 --------------------------------------------------------------------------
                  2.0                 0.5
 --------------------------------------------------------------------------
 
 *** Warning 10453 (KEY+453)
     blank line where command expected
          At line# 11 of file
 d:\lsdyna\restart\inputbalken_r.k
 
 *** Error 10133 (KEY+133)
     input data failed with: 2 errors

 E r r o r   t e r m i n a t i o n 

How do I use the *CHANGE_CURVE_DEFINITION command properly, or what am I doing wrong?

Thanks in advance!

              

[ErKo]

 

 

Hi

It is a tricky one not very well documented I would say.

 

The error is because it is not used that way – this keyword takes only LCID which is the curve to change.

 

In summary, if you want to change load cuve ID 5 say from the original model, you can set LCID=5 in the *CHANGE_CURVE_DEFINITION (see how this should look like below) and add the new *DEFINE_CURVE with ID=5 and the new values in the restart input file. But, the new load curve with ID=5 in the restart must have the same number of points as the curve LCID=5 in the original model (see help manual).

I find it easier to define a new curve (say ID=448) in the restart and use it there.

All the best

PS:

*CHANGE_CURVE_DEFINITION
$       ID
$#    lcid
         5
*DEFINE_CURVE
$       ID      sidr       sfa       sfo      offa      offo    dattyp   unused1
$#    lcid      sidr       sfa       sfo      offa      offo    dattyp     lcint
         5         0       0.0       0.0       0.0       0.0         0         0
$#                a1                  o1
                 0.0                 0.0
$                 a1                  o1                                 unused1
                 2.0                0.50