Select Close. Your screen should look like the following:

Region #1 has now been created but note that the cursor is still a cross-hair and the current operating mode in the status bar is “Draw regions”.

¾ To draw the second region of the problem 1. Move the cursor near (10,0) and click.

2. Move the cursor near (10,20) and click.

3. Move the cursor near (38,20) and click.

4. Move the cursor near (10,0) and click. The second region will be created with a default mesh, and the Region Properties dialogue box will once again appear.

5. Select the Elements Tab and ensure the secondary nodes box is unchecked.

6. Select the Edges Tab. Edge 3,4 should have a Min subdivision value of 5. Highlight Edge 4,5 and type 7 in the Min edit box. Select Copy to write this information to the list box. Your screen should look like the following:

7. Select Close.

Region #2 has now been created but note that the cursor is still a cross-hair and the current operating mode in the status bar is “Draw regions”.

1. Define Region #3 by clicking on points (0,20), (0,25), (10,25), (10, 20) and (0,20). The Regions Properties dialogue box will reappear.

On the Material Tab, select “2” from the drop down menu beside Material Type as shown below:

2. Select the Elements Tab and select the secondary nodes check box.

3. Select the Edges Tab. Highlight Edge 2,7. Type 5 in the Min. edit box.

4. Select Copy.

5. Select Close. The screen should look as follows:

Define the last region in a similar fashion.

1. Move the cursor and click in the following locations. (10,20), (10,25), (38,25),(38,20) and (10,20).

2. In the Regions Property dialogue box select the Material Tab, select

“2” from the drop down menu. Select the Elements Tab and ensure the secondary nodes option is unchecked.

3. Select Close.

4. Click the right mouse button to exit from “Draw regions” mode.

At this point, the problem has been completely discretized and should look like the following:

View the node numbers

Although nodes and elements have now been generated, the node and element numbers are not displayed on the drawing. Currently only region numbers and region points are displayed.

¾ To view node numbers on the drawing:

1. Choose Preferences from the View menu. The following dialogue

box appears:

The Preferences group box can be used to check or un-check any of the options found in the Items to View group box. The Font size and type can be set for points, regions, nodes, elements and axes using the Font Size group box options. Checking the Convert All Sketch Text Fonts option and selecting a font will convert all of the sketch text to the corresponding font.

2. In the Items To View group box under Mesh Information, check the Node Numbers check box to display node numbers on the drawing 3. Type 4 in the Node # Font Size edit box.

4. Select OK.

You can also select and unselect the View Preferences by clicking on the icons in the View Preferences toolbar. You can learn about each of the icons by placing the cursor over the icon. A tool tip will appear for a few seconds and a description is displayed on the status bar at the bottom of the window.

Specify boundary conditions

Boundary conditions can be specified at nodes as displacement, force, or spring stiffness. You can also specify pressure boundary conditions along element edges.

The boundary conditions for this tank settlement problem are:

• Displacement is zero in both the x- and y-directions along the right vertical boundary and along the bottom horizontal boundary.

• Along the left vertical boundary, the soil cannot move in the x direction but is free to move in the y-direction.

• Pressure is 40 kPa where the tank contacts the ground.

• Along the exposed ground surface, the soil is free to move in both the x and y directions.

¾ To specify the pressure boundary conditions applied by the tank:

1. Use the Zoom In button on the Zoom Toolbar to bring the area under the tank into closer view so you can see the node numbers.

2. Choose Edge Boundary Conditions from the Draw menu. The cursor changes from an arrow to a cross-hair and the status bar indicates that “Draw Edge Boundary Conditions” is the current mode. The following dialog box appears:

3. Select Normal/Tan Stress from the drop down menu in the Type edit box. Both stresses are defaulted to 0.0.

4. Type 40 in the Normal edit box (a positive value indicates a compressive stress). Since tangential stress is not applied, no action is required for the Tangential edit box.

5. Move the cursor near the top left corner of the mesh (-1, 26) and hold the left mouse button down.

6. Drag the mouse along the top of the mesh so that a rectangle encompasses all the edges along the bottom of the tank (Node numbers 21,32, 53, 64, 85, 96, 117, 128, 149, 160 and 181). Then, release the left mouse button.

Blue arrows are drawn pointing in a normal direction to the selected edges, indicating that a normal force is applied at these edges. A thick, blue line is displayed indicating that the pressure is being applied along the edge of the elements.

7. Click the right mouse button (or select Done) to finish defining the tank pressure boundary conditions.

8. Use the Zoom Objects button on the Zoom Toolbar to ensure all defined objects appear within the view window.

¾ To specify the x condition at the upper left corner of the mesh:

1. Choose Node Boundary Conditions from the Draw menu. The following dialog box appears:

2. In the X-Boundary Type drop-down list box, select X Disp. as the X-boundary type. Leave the values in the X Boundary Action edit box and the Fn.# as zero.

3. Click on the upper left corner of the mesh (Node 21), and a

zero-displacement symbol appears next to the node.

Do not close the Draw Node Boundary Conditions dialog box, since it will be used to define the remaining boundary conditions.

¾ To specify the boundary conditions along the right vertical and bottom horizontal boundaries:

1. Select X Disp. in the X-Boundary Type drop-down list box.

2. The X-Boundary Action edit box should be set to the default value of 0. If not, Type 0.0 in the X-Boundary Action edit box

3. Select Y Disp. in the Y-Boundary Type drop-down list box.

4. The Y-Boundary Action edit box should be set to the default value of 0.0. If not, Type 0.0 in the Y-Boundary Action edit box.

5. Select all nodes along the right vertical and bottom horizontal boundaries of the mesh. While you can click on each node

individually, the easiest way to select the nodes is to drag a rectangle around all nodes along the bottom of the mesh and then to drag a rectangle around all nodes along the right side of the mesh.

As each node is selected, two zero-displacement symbols are drawn at the node;

indicating that the specified displacement is zero in both directions.

The Draw Node Boundary Conditions dialog box can be moved out of the way if necessary, by clicking inside the title bar and dragging the box to a new position.

This is useful when the dialog box blocks the display of the nodes.

Do not close the Draw Boundary Conditions dialog box, since it will be used to define the remaining boundary conditions.

¾ To specify the boundary conditions along the left vertical boundary:

1. Click the down arrow beside the Y-Boundary Type edit box, and select (none) from the drop-down list. Use the remaining default values in the dialog box: