How to define surface contact in 2D analyses

For linear static stress analysis of two-dimensional (2-D) assembly models that are created using Autodesk Simulation’s sketching, modeling and meshing capabilities, you can conveniently and quickly define contact between parts. To do so, use the following general method:

1. Sketch the 2-D parts (the parts must share at least one identical-length, coincident edge).
2. Select the sketches in the tree view and click on the “Generate 2D Mesh” button within the “Mesh” panel under the “Mesh” tab (see Figure 1). The "2-D Mesh Generation" dialog will appear.

Figure 1: In the tree view, select the sketches that share a coincident edge and then click “Generate 2D Mesh” to access the "2D Mesh Generation" command.

3. Adjust the mesh settings as necessary and press “Apply” to generate the mesh.
4. In the model display, select the coincident surfaces and right click. In the pop-up menu, choose "Contact" and then specify the type of contact from five applicable options (see Figure 2):
• Bonded - The nodes on the two edges will be matched and will be in perfect contact throughout the analysis. When a node on one edge deflects, the node on the adjoining edge will deflect the same amount in the same direction. This is the default option.
• Free/No Contact - The nodes on the two edges will not be matched and will be free to move relative to each other.
• Surface Contact - The nodes on the two edges will be matched and will be free to move away from each other. If the nodes move toward each other, a stiffness will be applied to resist this movement.

o   Sliding/No Separation – Bonds contact faces in normal to face direction while sliding under deformation.

o   Separation/No Sliding – Separates contact faces partially or fully without them sliding against each other.

Note that Edge Contact and Welded Contact are not applicable to 2D elements.

Figure 2: Once the mesh is generated, you can select and right click on the coincident surfaces and specify the type of contact.

4. After defining the type of contact, the contact surfaces will be listed in the tree view.
5. In the tree view, right click on the contact pair and choose "Settings..." (see Figure 3).

Figure 3: Right click on the contact pair in the tree view and choose "Settings...".

6. In the "Contact Options" dialog, you can specify the coefficient of friction for the contact pair (see Figure 4).

Figure 4: Choose whether or not to include friction in the analysis and specify the static friction coefficient.

7. Set up for linear static stress analysis (define element information, material properties, loadings and constraints) and run the analysis.
8. In the Results environment, you can inquire on the total contact force for each contact pair in the model. Right click on the heading for the contact pair in the tree view and choose the "Contact Force..." command (see Figure 5).

Figure 5: In Results environment, you can inquire on the total contact force. A "Total Contact Force" dialog will appear with the total contact force for that pair.

Thus, the ability to quickly and easily define 2-D contact helps you to perform linear static stress analysis of 2-D assembly models that were created with Autodesk Simulation’s sketching, modeling and meshing tools.