Learning Forum

[Thomas Lowery]

I am simply looking to simulate the contact between two rings made of beam elements using the thickness of the beams as the contact "surface". 

 

The manual mentions beam-to-beam contact:
*CONTACT_AUTOMATIC_GENERAL is a
single surface contact similar to *CONTACT_AUTOMATIC_SINGLE_SURFACE
that also includes treatment of beam-to-beam contact and in doing so,
checks along the entire length of the beams for penetration.

But my rings don't see each other with this turned on:

*CONTACT_AUTOMATIC_GENERAL_ID
$#     cid                                                                 title
         1                                                                      
$#   surfa     surfb  surfatyp  surfbtyp   saboxid   sbboxid      sapr      sbpr
         0         1         2         2         0         0         0         0
$#      fs        fd        dc        vc       vdc    penchk        bt        dt
       0.0       0.0       0.0       0.0       0.0         0       0.01.00000E20
$#    sfsa      sfsb      sast      sbst     sfsat     sfsbt       fsf       vsf
       1.0       1.0       0.0       0.0       1.0       1.0       1.0       1.0

[Alex R.]

Hello Thomas, 

In a single surface contact (A_GENERAL and A_SINGLE_SURFACE) the elements should be on a surfa (slave) side of a contact. Master side (Surfb) is not applicable for single surface contact. 

In your case slave (surfa) is null. To make this contact work change SURFA with SURFB, assuming that Set PID = 2 exists. 

Please find out the article about beam-to-beam (shell_edge) contact: /knowledge/forums/topic/how-to-model-contact-between-beam-elements/

Thank you,
Alex 

[Thomas Lowery]

I am not have any success with this, I switched to using a mortor contact as suggested by the link.  What I expect to happen is that I have two simple rings made of beams, I fixed one under the other can turn gravity on and the top ring should fall and bounce off the fixed bottom ring.  But it seems no matter what I do they just pass thru each other.

*CONTACT_AUTOMATIC_SINGLE_SURFACE_MORTAR_ID
$#     cid                                                                 title
         1                                                                      
$#   surfa     surfb  surfatyp  surfbtyp   saboxid   sbboxid      sapr      sbpr
         1         0         3         3         0         0         0         0
$#      fs        fd        dc        vc       vdc    penchk        bt        dt
       0.0       0.0       0.0       0.0       0.0         0       0.01.00000E20
$#    sfsa      sfsb      sast      sbst     sfsat     sfsbt       fsf       vsf
       1.0       1.0       0.0       0.0       1.0       1.0       1.0       1.0
*PART
$#                                                                         title
Ring 1
$#     pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         1         1         1         0         0         0         0         0
*SECTION_BEAM_TITLE
Ring 1
$#   secid    elform      shrf   qr/irid       cst     scoor       nsm     naupd
         1         1       1.0         2         1       0.0       0.0         0
$#     ts1       ts2       tt1       tt2     nsloc     ntloc
     0.226     0.226       0.0       0.0       0.0       0.0
*PART
$#                                                                         title
Ring 2
$#     pid     secid       mid     eosid      hgid      grav    adpopt      tmid
         2         2         1         0         0         0         0         0
*SECTION_BEAM_TITLE
Ring 2
$#   secid    elform      shrf   qr/irid       cst     scoor       nsm     naupd
         2         1       1.0         2         1       0.0       0.0         0
$#     ts1       ts2       tt1       tt2     nsloc     ntloc
       0.2       0.2       0.0       0.0       0.0       0.0
*SET_PART_LIST
$#     sid       da1       da2       da3       da4    solver
         1       0.0       0.0       0.0       0.0MECH
$#    pid1      pid2      pid3      pid4      pid5      pid6      pid7      pid8
         1         2         0         0         0         0         0         0

 

[Alex R.]

Hello Thomas, 

In your contact SURFATYP = 3 means a single part, PID = 1. In your case you should use SURFATYP = 2 Part set ID. 

Please try *CONTACT_AUTOMATIC_GENERAL. 

Thanks,
Alex