Learning Forum

[sockalin]

Hello,

How should the load segment and segment set be defined for 2D plane stress geometry modeled using Q8 elements elform = 23? Each edge has 3 nodes. 

Thanks.

[ErKo]

 

 

Hi

So ELFORM=23 belongs to the shell family (like Hughes Liu shell), and like ELFORM=16 (4-node shell),

 

rather than the 2D continuum family represented by ELFORM=13 and ELFORM=15 that are for 2D plane stress and axissym. 2D analysis.

Perhaps someone else has some ideas on how to create for segments of 3 nodes (seems that LSPP does not account for midside nodes)

All the best

 

Erko

 

 

[sockalin]

Hello,

Thanks. Tried using LSPP to create a segment on the edge. It does not appear to detect the mid side node. It defines the segment as shown below. This definition does not seem to apply the loads during the simulation. 

*SET_SEGMENT_TITLE
left edge
$#     sid       da1       da2       da3       da4    solver       its         -
         1       0.0       0.0       0.0       0.0MECH               0          
$#      n1        n2        n3        n4        a1        a2        a3        a4
         2         1         1         1       0.0       0.0       0.0       0.0
         3         2         2         2       0.0       0.0       0.0       0.0
         4         3         3         3       0.0       0.0       0.0       0.0
         5         4         4         4       0.0       0.0       0.0       0.0
         6         5         5         5       0.0       0.0       0.0       0.0

[ErKo]

Perhaps someone else has some ideas on how to create for segments of 3 nodes (seems that LSPP does not account perhaps for midside nodes).

In the meantime just use LOAD_NODE_SET , and choose all of the nodes on that edge.

All the best

Erko

[Dennis Chen]

I adjusted a previous model I made to try this and is below what you are hoping to see?  if so, you can do this using the mesher inside workbench ls-dyna.   Using a 2D analysis, change element order to quadratic and plane-strain so elform 13 is written out into the input file.   

Hope this helps.   I also made a video last week on this topic but it's not related to mid-side node, I adjusted it just now to try out the idea.