Node Interaction in Mechanical, Part 1: Picking Your Nodes

NosePicking1In version 14.0 of ANSYS Mechanical, ANSYS has rolled out its first capabilities for interacting with the underlying finite element model in addition to the geometry. In this version, the user can select nodes, create named selections from nodes, apply loads and constraints to nodes, and scope results to nodes. And it is glorious. In this posting, the first part in a four-part series on interacting with nodes in Mechanical, I will start of with the basics: selecting nodes in ANSYS Mechanical.

The default picking mode in Mechanical is to Select Geometry. In order to select nodes you will first need to display the mesh by either highlighting the Mesh branch or by clicking the Show Mesh (image) button. Next, switch the select mode to Select Mesh under the Select Type pull-down.

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At this point you will be able to pick nodes in the same manner that you pick vertices. Note that the entity filter is automatically set to Vertex when you’re in Select Mesh mode, so you may need to reset the filter once you go back to Select Geometry mode.

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You can also box select or lasso select nodes under the Select Mode pull-down. Note that there are two options for each: plain ol’ box and lasso select, and box and lasso volume select.

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I’ve found that volume select vs. regular select is best illustrated using flat surfaces, so here we go: an example with flat surfaces.

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Regular box or lasso select only selects nodes on the faces closest to the viewer.

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Note: To lasso select, simply click and drag the cursor around in a loop.

On the other hand, volume select selects all the nodes throughout the depth of the model.

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A related question that has come up when I demonstrate the new nodal interaction capabilities is, “Node numbers! Where are my node numbers? I want to see node numbers! Give me my node numbers!” OK, you can view node numbers now. (You can also view information about other entities, but this is a blog post about nodes, so I’m going to talk about nodes.) To view node information, first make sure you’re in node-picking mode, select the nodes of interest, and then click on the toolbar button featuring the blue ‘i’ with a black arrow next to it.  image (You can also do this in reverse order. Whatever floats your boat.) When you do this, the Selection Information will display the node X, Y, and Z location and Node ID in the lower left corner of the GUI.

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If you had picked two nodes, it would also show the distance between those nodes. You can customize the display by clicking the green check box, though you probably won’t want to change anything with the node display.

In the next installment I will show you how to create nodal Named Selections starting with simple picking and moving on to such criteria as location, node number range, and nodes attached to solid model entities. This knowledge will come in handy for applying boundary conditions to nodes and scoping results to them, which I’ll cover in the third and fourth installments. Happy node picking!

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