Define a Simple 3D Element
- This example explains Continuity's convention for interpreting element definitions and then guides the user through a simple exercise to check understanding.
The cont6 file contains all data and parameters for this problem.3delem.cont6
Understanding the Continuity Element Definition Convention
An element definition tells Continuity how to connect nodes to one another to form elements
The element definition is entered into the Elements Form as global node numbers separated by commas
A 1D element consists of 2 nodes, so an example of a 1D element definition is: 11,14
A 2D element consists of 4 nodes, so an example of a 2D element definition is: 11,14,18,19
A 3D element consists of 8 nodes, so an example of a 3D element definition is: 11,14,18,19,21,23,27,29
The order in which the global node numbers are listed determines how nodes are connected
The significance of this order is explained by the convention below, which is specific to Continuity and has no particular meaning outside of it.
- Study the following example:
Try it for yourself
Now that you've seen a few examples, try it for yourself in Continuity. A set of eight nodes has already been set up for you with GLOBAL element numbering that looks like this:
- Follow the step-by-step instructions below to load the nodes into Continuity, then try your hand at defining an element
- Launch the Continuity 6.3 Client
check the Mesh module box under Use Modules:
Select rectangular cartesian in the Global Coordinates: pop-up menu
Click OK to submit Coordinate Form
Choose Lagrange Basis Function→3D→Linear-Linear-Linear with 3 integration/collocation points for Xi 1, Xi 2, and Xi 3
Click OK to submit Basis Form
Click Import/Export/Graph button to open Continuity Table Manager
Select tab-delimited nodes file attachment:nodes.xls
Select Linear-Linear-Linear Lagrange 3*3*3 under Coordinate 1, Coordinate 2, and Coordinate 3
Click OK to submit Node Form
At this point, follow the step-by-step example at the top of this page for defining an element, BUT note that the global element numbering is different.
- Note that for step 1, you may choose ANY node to be your element origin
- Also note that for step 2, you may choose ANY of the nodes connected to your element origin to define Xi 1
Click OK to submit Element Form
Render the Result
Click the lines radio button
Click Render to display mesh lines
- The rendered element should look something like this (after zooming and rotating appropriately):
- If the element lines look jumbled or wrong, you've made a mistake in your ordering. Re-open the elements form and try it again.
Once you've clicked OK in the elements form, you'll have to repeat the steps under Render Results to see the change.