General Mechanical

General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

I can’t find the difference in this model (autodyn)

    • Ahmed Taher


      i have tried my best figuring out where the difference or mistake in my model is, i ran an analysis for a contact conical charge to a column mid-height, the results weren't as anticipated. To end my doubt, i tried to mod the problem again, but this time, results are quite different and way better than before. The thing is, i literally compared everything between the before and the latter models and both are literally the same.


      i have checked the: materials and their parameters, parts, meshes (I evem tried different meshes thinking this is the reason of difference), gap size, joins and merging joined strucutre nodes (after importing to IJK parts to instructured).. everything is the same between the two models. here are some photos:

      first model: (the not anticipated results)












      the second model (better results):





      both pictures were captured at the same point of time, and as shown, the second model having a lot of eroded concrete and 5 stirrups shown, whilst the first having much less eroded concrete and 2 stirrups are shown. I can't figure out what the problem might be.




    • Chris Quan
      Ansys Employee

      Are you using Autodyn Component system? If yes, you need to check if the solid elements are connected with the beam elements in your model for both simulations.

      In AUTODYN GUI you can JOIN two parts together from the left navigation bar by click on JOINS -> Join, select parts from dialog window, and then click APPLY to join these parts together.

      JOIN acts like bonded contacts in ANSYS Workbench Mechanical GUI. Please be aware that JOIN logic in Autodyn GUI is different between structured (IJK-based) mesh and unstructured mesh. 

      For IJK-based mesh, you need to make sure all nodes on the joining interface from each part match each other. Otherwise, parts won’t be joined together. In your model, the beam nodes from line bodies have to match the nodes of Lagrange elements from solid body. You can plot grid of your joined parts to make sure nodes on the interface match each other.  
      For unstructured mesh, nodes are not necessarily matching each other at the joining interfaces. You can create Bonded Face Connections to join surfaces together. You can create new groups of faces via GROUPS -> NEW -> POLYGON ADD for bonded face connections. In your model, you need to make sure the line bodies are alingned with the edges of Lagrange elements but their nodes are not necessarily matching each other.
      Finally, you can plot the Joined Nodes or Joined Parts using Joins from the left navagation bar and then check the box of "Plot joined nodes" or "Plot joined parts" to confirm the properly setup of Joins.


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